This means that one of the files Windows needs to load has become corrupted.
The easiest method requires a full retail version of Windows CD (not a OEM “recovery disk”), or that you have previously installed the Recovery Console…if you don’t know what the RC is, you probably haven’t installed it. (use a search engine to look up “installing the Recovery Console”.)
1) boot to the Windows CD and let the files load as if Windows was installing itself. When that’s done,
2) select “r”, for Recover
You will be asked which Windows you want to log onto and repair (usually you only have one choice) so type in a 1. If you need a password to log into Windows Administrator’s account (usually your account) enter it now. If you don’t use a password, just hit Enter key.
You will now see a DOS prompt blinking at you. Type in the following (without the quotes) “fixboot c:”
You should now be good to go.
If all you have is a OEM “recovery” disk, your choices are much more limited, and you’ll usually wind up with a fresh install of Windows. You may, or may not lose your data…but you’ll definitely have to re-install your applications, and re-patch and re-update, and re-install any device drivers for specialty devices (like sound cards).
See if you can’t borrow a retail install Windows disk?