If you try to run an old DOS game on Vista, you'll probably get an error "This system does not support fullscreen mode." Fortunately, this isn't a dead end.
Re-installing Windows can be a traumatic business, it's bad enough having to backup all of your data and re-install your programs but the worst bit is tracking down all of the drivers for your hardware and peripherals.
That's right! There is a hack available that will permit you to access, download and install the official release of Windows Vista Service Pack 1 straight from Microsoft.