Two words. Reinstallation Disc.
Depends on the O/S you're playing with. Windows 2000 + XP isn't DOS based and the friendly Windows 98 commands such as Format and Fdisk have been replaced by a setup management utility found on the Windows 2000/XP program CD. Note that an off the shelf generic CD for installing Windows won't necessarily have the specific drivers for your machine, but you don't need to know anything about this.............
........as it's best to play the get out of jail free card. Simply enter the Bios to change the boot sequence to the CD-ROM drive (any prat can do it, I did) and boot from the manufacturer's reinstallation disc(s) . Takes about 40 minutes, O/S and required drivers are installed as you drink coffee and watch the computer do its thing. Very impressive it is too, sort of like having your computer amiably possessed by Bill Gates. Good idea though to keep the fingers crossed; if you're the nervous type take a snooze and it'll all be over when you wake up. Hopefully.
If you don't have a reinstallation disc set consider purchasing one from the manufacturer, they're not expensive. As you mentioned, any data on the Hard Drive will be lost, so save anything you want to keep, which is not that difficult as CD-RW burners are able to gobble up data in 800M blocks. There are ways of plugging programs around files left on the HD (CDs for doing this are available on eBay- surprise, surprise) but it's not a technique for the feint of heart.
Last edited by XL5; 15th March 2006 at 06:44.