How do I use the XP restore CD to fix a file?

I have been having some XP and browser issues for a couple of weeks. IE and Mozilla both shut down "due to a serious error". Also having problems with Norton Antivirus 2005 saying "repair function not working. Reinstall." It seems to have a conflict with the Popup and Spyware software provided by Cox internet cable. Here's the problem now. System wouldn't boot because
The following file is either missing or corrupt

Put in Restore CD. Enter "r" for repair instead of totally reinstalling windows. Leads me to the recovery console and get the following dos prompt C:\WINNT>

I have no experience restoring. The first time I tried this I got a lot of options to choose from like FIXBOOT, (which I typed in after the dos prompt). It didn't seem to do anything. What instructions am I suppose to give the machine from that dos prompt? Anyone?

Gateway P4 1.5 ghz
728 RAM
Service Pack 2
160 gig HD