download The Ultimate Boot CD (it's free)burn it to a disk, boot from the disk, select HDD tools and wipe 1 pass, when it's done remove the disk, put the Win installation disk in the drive and reboot the computer, install Windows
did you download Ultra ISO? and install it, drop the download into utra ISO(right screen on the top),and burn to a disk, it automatically makes a self Booting disk, put the cd in the computer and start, it will load automatically
start the program, click on the top left, Write Image File to Disk, in the next screen, top left, the icon with out the +sign, open the folder that has the ISO of UBCD and click Open, put a new cd in the burner, on the botom left the icon to the left of the disk icon, that should do it
Do you have the ISO? Go grab a 4GB USB Flash Drive!
If you have problems with the DVD install try this:
You can download the USB tool for free and copy your Windows 7 ISO to the USB. Complete instructions can be found here: http://store.microsoft.com/Help/ISO-Tool
I use USB flash drives all the time for OS install it works perfectly - lot faster and no DVDs to get scratched and damaged! :-)