I got this computer from my sister-in-law. It's only a couple of years old and I think the hardware's all good but her kids, in trying to 'fix' it, have it so mucked up that you can't even get online with it. I don't have a 2000 disk but I do have a 98 disk that hasn't been used except for repairs (never registered). So how do I do this?

I asked this last night but I didn't understand the answers. They made it sound like all I had to do was put in the 98 CD and let 'er rip. Can that be right? They also mentioned formatting, which I don't know how to do. I tried googling it but that was even more complicated. Can anybody help with this?

Btw, the computer doesn't have Ad Aware or Spybot or anything like them any more, so I can't fix 2000.
Didn't work. It formatted the drive, then claimed it was starting setup. Then it said CDR101: Not ready reading D. At one point it said Scandisk.exe could not be found and it could not continue. Mostly it just says not ready reading D. Can't get past that.
This is actually an installation disk. What went wrong?