I know how to do a basic format, but not the proper deap format. This one takes just 2 mins to do and gets rid of most things!!! In dos type,
" format c: /s "
Then go into bios settings and set the boot settigns to
" cdrom, c, a "
Or so that cdrom is at the start. Then pop in your windows disk and the on screen instructions will guide you into loading windows again. If it refuses to load, type "setup" in dos and that should work.
Just make sure you have all your drivers ready and that they work.
Some real computer boffin would be better help, but this should cure your problem. Hope that was any help.