32-bit hardware and software is often referred to as x86 or x86-32. 64-bit hardware and software is often referred to as x64 or x86-64.
32-bit systems utilize data in 32-bit pieces while 64-bit systems utilize data in 64-bit pieces. In general, the more data that can be processed at once, the faster the system can operate. There are several other advantages to a 64-bit system as well, most practically the ability to use significantly greater amounts of physical memory.
Most new processors today are based on the 64-bit architecture and support 64-bit operating systems. These processors are also fully compatible with 32-bit operating systems.
Most editions of Windows 8, Windows 7, and Windows Vista are available in 64-bit format. Only Windows XP Professional is available in 64-bit. All editions of Windows 8, Windows 7, Windows Vista, and Windows XP are also available in 32-bit.
Not Sure if the Copy of Windows on Your PC is 32-bit or 64-bit?
See Am I Running a 32-bit or 64-bit Version of Windows? to find out.
"I tried several times to download and install an updated driver for my sound card but I just couldn't get it to work. I finally realized that I was trying to install the 32-bit driver when I should have been installing the 64-bit version. I have Windows 7 Ultimate 64-bit so all the drivers I install must be 64-bit based for my 64-bit operating system."