You may have problems with hardware you don't even know about. Here's a way to check for these and correct them. I recently had to do a clean install of Windows 7 on a friend's laptop. Easy, right? Boot from the installer disk, and let Windows download all the appropriate drivers.
Not so fast. What if the very network driver, which allows this downloading of the rest of the drivers, wasn't working? That turned out to be the case with my laptop upgrade.
