By default, Windows Vista generates a preview thumbnail for nearly every file when viewed in Windows Explorer. Yes - thumbnails can be really useful for quick photo viewing, but disabling these thumbnail previews in Windows Explorer can really speed things up.
Disabling Vista's thumbnail previews in Windows Explorer is really easy to do and should really improve response time when browsing around your drives.
Click on the Start button.
Tip: Are you quicker on the keyboard than on the mouse? Type windows explorer in the search box and hit the Enter key. Skip to Step 4.
Choose All Programs, right above the search box.
Click on the Accessories folder and then the Windows Explorer link.
After Windows Explorer loads, click on the Organize button and choose Folder and Search Options from the menu.
In the Folder Options window, click on the View tab.
Under the Files and Folders heading, check the box next to Always show icons, never thumbnails.
Click the OK button.
From now on, no matter which view you're using in a folder in Windows Explorer, no thumbnail will be generated. This should greatly increase the speed at which you can move between folders and may even speed up copying and other tasks in Windows Vista.