One of the more popular Windows 8 tutorials on my site is the How To Clean Install Windows 8 walkthrough so there's little doubt why Windows 8 and Windows 8.1 installation and upgrading questions are some of the more common ones I get.
Below are answers to some of those questions. I'll add more Q&A's as time goes on but feel free to let me know if you think something should be addressed here, or check out Get More Help if you've read through these but are still having trouble.
"I read that I should do a 'clean' install of Windows 8. How do I do that? Do I need a special disc or instructions?"
Basically, a clean install means to erase the drive with the existing operating system on it during the process of installing Windows 8. This differs from an upgrade installation ("moving" from a previous Windows version) or a new installation (install on an empty drive).
Compared to an upgrade installation, a clean install is almost always the better way to install Windows 8. A clean install won't bring with it any problems, software bloat, or other issues that may have plagued your previous installation.
No, you do not need a special Windows 8 disc, or any sort of other software or tools to do a clean install. All you need to do is remove the partition(s) that contain your existing operating system when you get to that step in the Windows 8 installation process.
See How To Clean Install Windows 8 for a complete tutorial, including screenshots. This tutorial applies to Windows 8.1 as well.
"Can I clean install Windows 8 using a Windows 8 Upgrade download or DVD?"
Yes, you absolutely can clean install Windows 8 using an upgrade-licensed copy of Windows 8 or Windows 8 Pro. This includes both the Windows 8 Upgrade downloads from Microsoft and the Windows 8 upgrade discs that were both available prior to the Windows 8.1 update.
If you have one of the Windows 8 Pro Upgrade downloads from Microsoft, see How To Clean Install Windows 8 Pro Upgrade for a walkthrough on how to properly prepare that download so you can use it for a clean install.
If you have a Windows 8 upgrade version in DVD format that you purchased from a retail store or online, there's nothing to prepare as long as you have an optical drive. If you need that disc on a flash drive, see How To Install Windows 8 From a USB Device for help doing that. It's not as easy as copying the files to the flash drive so be sure to look at the tutorial before getting started.
Important: You can only install Windows 8 (clean install or upgrade install) using an upgrade license if you currently have a copy of Windows 8, Windows 7, Windows Vista, or Windows XP installed on the computer. True, the clean install process involves removing that operating system, but it still has to be there when the Windows 8 setup process begins. Upgrade licenses were less expensive than full licenses because you're getting a break as a previous Windows customer.
There is no upgrade licensed version of Windows 8 beginning with the 8.1 update. If you purchased Windows 8.1 as a download or on disc then this issue doesn't concern you at all.
"I got a 'Invalid product key' message with a 'Code: 0xC004F061' error! What's wrong?"
Here's the full error message, all inside an Invalid product key window:
The following failure occurred while trying to use the product key: Code: 0xC004F061 Description: The Software Licensing Service determined that this specified product key can only be used for upgrading, not for clean installations.
The message at the bottom of the window indicates that you can't use this product key for clean installations but that isn't entirely true. A Windows 8 clean install is fine, but you must have had an upgrade-valid version of Windows on the computer prior to the clean install.
The Microsoft-supported solution to this problem is to reinstall the previous version of Windows and then clean install Windows 8. However, I'm told that another solution is to do an in-place upgrade of Windows 8 to... Windows 8. Yes, it seems strange, but according to several sources, you'll be able to successfully activate Windows 8 after that process completes.
If neither of those solutions work, you'll need to purchase a Windows 8 System Builder disc (sometimes referred to as an OEM disc) which you will be able to "new" install on an empty hard drive or clean install over a non-upgrade-valid version of Windows (e.g. Windows 98, etc.) or a non-Windows operating system.
Note: It's important to realize that during the Windows 8 clean install process, when you enter your product key, you are not warned about the possibility that you're using the wrong key. That stage in the Windows 8 installation process just checks to see if the product key is valid at all, not if it's valid for your specific situation. That determination occurs during the activation process after Windows 8 is completely installed.
If you have more product key specific questions, see my Windows Product Keys FAQ page for more help.
"I'm confused about the upgrade and full versions of Windows 8. Can you explain the difference?"
Prior to the sale of Windows 8.1 on disc and download, Microsoft sold upgrade versions of Windows 8 Pro and Windows 8 (standard) allowing you to perform an in-place upgrade, or a clean install, from Windows 7, Windows Vista, or Windows XP. In other words, you had to have one of those three versions of Windows installed if you wanted to be able to purchase this less expensive Windows 8 license.
Microsoft finally ended that confusion with Windows 8.1 and now offers full retail licenses at the discounted (and now permanent) upgrade-level price.
You can read more about current and previous Windows 8 licenses in that section on my Basic Windows 8 Information page.
"I have Windows 8 on a DVD but I need it on a flash drive. How do I do that?"
See How To Install Windows 8 From a USB Device for a complete tutorial. Unfortunately, it's not as easy as just copying the files on the Windows 8 installation disc to an empty flash drive.
"I downloaded Windows 8 but all I have is an ISO file. How do I get that on a DVD or flash drive so I can clean install Windows 8?"
That ISO file you have is a perfect image of a Windows 8 installation disc, contained in a neat one-file package. However, you can't just copy that file to a disc or a flash drive and expect to use that to install Windows 8.
If you want to install Windows 8 from a DVD, see How To Burn an ISO File to a DVD for instructions.
If you want to install Windows 8 from a flash drive, you can follow the same tutorial as I linked to in the last question: How To Install Windows 8 From a USB Device.
"I have Windows 8/8 Pro installed on my PC. If I replace the PC with another, can I install my copy of Windows 8 on my new PC as long as I remove it from the previous one?"
Yes. The biggest point is the one you mentioned: you must remove Windows 8 from the old computer before you activate it on the new one. In other words, you can only have your copy of Windows 8 or Windows 8 Pro running on one computer at a time.
Another thing to keep in mind is that if you installed an upgrade licensed copy of Windows 8 on a computer and then want to use it on another computer, the same "upgrade rules" apply: you'll need to have a previous version of Windows on the computer before installing Windows 8. You can ignore this rule if you started with Windows 8.1
Important: You can not "move" Windows 8 or Windows 8 Pro to another computer if Windows 8 came preinstalled on your computer. Your copy of Windows 8 is OEM licensed which means that you are only allowed to use Windows 8 on the computer that it came already installed on.
"How many times can I reinstall Windows 8 on another computer? Assuming I follow the 'uninstall the old installation' rule, can I keep installing Windows 8 on different computers?"
There are no limits to the number of computers that you reinstall Windows 8 onto so long as you follow the rules I discussed in the last question.
"Do I have to buy another copy of Windows 8 if I want to install it on another computer?"
The answer to this is probably clear if you've read the last few answers, but: Yes, you will need to buy a license to install Windows 8 on each and every computer or device you plan on using it on.
"I restarted with the Windows 8 DVD/flash drive in my computer but the Windows 8 setup program didn't begin. What happened?"
See How To Change the Boot Order in BIOS or UEFI for help.
"Help! My computer froze/restarted/got a BSOD during the Windows 8 install!"
Try installing Windows 8 again. Sometimes problems during a Windows 8 installation are temporary so another shot is a good first step. If you're doing a clean install, just start the process over again. Since part of a clean install involves formatting the drive, whatever issues might exist with this partial installation will be gone.
If just starting the Windows 8 install over again doesn't work, try removing/unplugging any unnecessary hardware from your computer before starting the installation process. The Windows 8 setup process could stall or produce an error if it's having an issue installing some piece of hardware. It's much easier to troubleshoot an installation problem with a piece of hardware once Windows 8 is up and running.
Finally, be sure that your computer's BIOS or UEFI is updated. These updates by your computer or motherboard manufacturer often correct compatibility issues with operating systems like Windows 8.
"How does Windows 8 already know my phone number?"
Near the end of the Windows 8 setup process, if you choose to use a Microsoft Account to sign in to Windows 8, you'll be asked to provide or verify your phone number.
If your phone number is already listed, it just means that you've previously provided it to Microsoft when you created your Microsoft Account. You probably have a Microsoft Account if you've ever logged in to another Microsoft service in the past.
"Windows 8 costs almost $200 USD to download?! I thought it would cheaper since it's a download and not a boxed copy!"
The majority of what you're paying for is the license to use Windows 8 so downloading it isn't advantageous from a cost standpoint as much as it is from an ease-of-use or quick turnaround perspective.
That said, I don't know exactly why you were after a download of Windows 8 so there are a few other methods that might apply to your situation. See Where Can I Download Windows 8? for some ideas.
"Is upgrading from Windows 8 to Windows 8.1 free?"
Yes. To be clear, if your computer is already running Windows 8, then yes, you can apply the free update to Windows 8.1 from the Windows Store.
"Is upgrading from Windows 8.1 to Windows 8.1 Update free?"
Again, yes. This update is also free.
See my Windows 8.1 Update piece for more on upgrading to Windows 8.1 Update.
"Can I use a Windows 8.1 disc/flash drive or ISO image to update my copy of Windows 8 to Windows 8.1?"
Technically, yes, this is possible. Just insert the Windows 8.1 installation media and execute setup.exe to start the process.
However, if you "upgrade" this way, you will need a Windows 8.1 specific product key.
Since installing or upgrading to Windows 8.1 from dedicated media is intended for new computers or upgrades from older versions of Windows, this isn't a good way to move from Windows 8 to Windows 8.1. You're much better off applying the free update from the Windows Store.
"If I started with Windows 8, updated to Windows 8.1/8.1 Update, and then do the Refresh My PC or Reset My PC thing, will it take me all the way back to Windows 8?"
Unfortunately, your installation will be taken back to Windows 8, meaning you'll have to update to Windows 8.1 Update all over again.
"Can I update from Windows 8 (standard) to Windows 8.1 Pro?"
No, not directly. If you have Windows 8 and apply the 8.1 update, you'll go to Windows 8.1. If you have Windows 8 Pro and apply the 8.1 update, you'll go to Windows 8.1 Pro. The same logic applies to Windows 8.1 Update upgrades.
If you want to update to Windows 8.1 Pro from the standard edition, I recommend applying the 8.1 update and then purchasing the Windows 8.1 Pro Pack to go to Windows 8.1 Pro.
"I'm using Windows 7/Vista/XP/Linux right now and want to install Windows 8.1. Is it better to buy/download a copy of Windows 8 and then update to 8.1 or should I just buy/download Windows 8.1? Same question with Windows 8.1 Update."
One method isn't better than another. It's your choice.
If you'd like to keep things less complicated, buy the most recent edition of Windows 8 that Microsoft is selling, since the updates are already included in the installation. It'll save a you step or two at the end of the day.
However, if you can find a discounted copy of Windows 8 or Windows 8 Pro (the older versions, without the 8.1 or 8.1 Update updates), then buying that and doing the super-easy update to Windows 8.1 Update could save you some money.
"I don't see KB2919355 in Windows Update! How do I install the Windows 8.1 Update update?"
KB2919355, the technical name for the Windows 8.1 Update package, requires that KB2919442 be installed first. If you skipped this update at some point in the past, that would explain this.
Check in Windows Update for KB2919442 and install it, then restart your computer and look for KB2919355 again. You can also manually download KB2919442 here.