Windows XP, a potential survivor to both Windows Vista and Windows 7.
You've heard it right! this includes every driver since the release of XP.
Before installation, unused devices should be disabled so as to avoid driver conflicts and to keep Windows as lite as possible. By example, disable onboard audio in the BIOS if you already have a dedicated audio card, or else if you have two graphics cards both plugged in either physically unplug the unused one or disable it in the device manager.
Once you've booted from the CD (takes a few minutes), create a system partition big enough to hold both Windows and the program files. Once inside Windows itself, you'll be able to create logical drives (using the disk management tool) and take the rest of the space back. I'd suggest doing a quick NFTS format because the normal one performs the additional step of verifying HDD health (which takes extra time). If you're serious about your data, you should instead routinely scan for errors using HD Tune.
The whole setup process usually takes about half an hour. When it's done and you're back on the desktop, remove the CD and begin with the driver installation (takes about an hour), then reboot and enjoy your fresh new operating system.