System32\Drivers\Ntfs.sys missing or corrupt

Ok I wanted to watch a DVD on my computer and Windows Media Player said I needed to add something so I was able to watch the video. So, I downloaded something and then I was getting all these pop ups. I am sorry I can't be more specific as I just don't remember what I did and the name of the program as when I got all this I removed it and ran spyware programs and deleted whatever infections said was there. Then I ended up with a Toolbar in Firefox called Somoto (or something like that) so I did the removal process for that and when my computer rebooted back up I can't get into anything even safemode it tells me System32\Drivers\Ntfs.sys file is corrupt or missing.

This is a computer that I got from someone else I do not have the Windows XP install CD or any CD's for that matter for this computer (person I got the computer from doesn't have any CD either). Now what? How can I boot up the computer so I can use it again? It is a Compaq Presario 6000