Can't install anything or shut down in XP home edition

I just fdisked and installed Windows XP Home Edition and now, about a week later, suddenly I'm having trouble installing anything. Especially windows updates. When I go to the microsoft web site and click on the install button, nothing happens. With most anything else I want to download the same thing happens. If I do actually download something, it freezes during the installation process and I have to use the task manager to close it.

On top of that, my computer won't shut down. It goes to the screen that says, "Windows is shutting down" or similar, and then stays like that. I have done all kinds of research on this, and most people say it has something to do with advanced power management, but I've gone to that screen and didn't have the ADP or whatever tab so clearly that's not the problem here.

I'm using a computer that I built last year. I have three hard drives, two 29-gig, and one 3-gig from an old computer, each with plenty of free space. I have a 1.5 GHz Pentium IV, and 256 MB RAM. I am dual-booting with the copy of XP home edition on one 29-gig drive, and a very messed up copy of XP Pro on the other 29-gig drive that I only use in emergencies.

I'm stumped. What's the problem?

 

If you have a restore point from before the problem started, roll back and see if you are cured.

start~run~sfc /scannow to examine all your system files and repair any that are bad.

Shutdown problems - if you have checked your BIOS and you are not set for Advanced Power Management, then video problems would be a likely suspect. Maybe the card itself or maybe the drivers you have loaded.