Originally Posted by cyrnel

I'd probably be booting another system with your drive on the side to inspect what happened. It isn't easy to recover when the tools are inaccessible.

This might be the time to run a repair from the XP install CD.
-Boot from the CD.
-At the first prompt select "Install" (not repair with recovery console)
-It should search for existing installs. Assuming it shows yours select "Repair".

You'll want to run windows update after. That's assuming it comes back to life.