I don't know for how long I've had this problem, but two weeks ago I couldn't use some Windows 2000 services. The first thing I noticed is Add/Remove programs, as soon as I opened it, it froze and would never respond. I've also tried to run Windows Update, but IE freezes as soon as I open the website. I've done a virus scan, (AVG) a spyware/adware scan (SUPERAntiSpyware) and I've used HiJack This!. I compared my current HJT log to a previous one that was fixed on this website and there was no change. I've also left Windows Update and Add/Remove programs open for about 10 minutes and nothing happened.

Could be:
Program conflict in background
corrupted firewall/antivirus-- any program can be corrupted--even IE itself could be corrupted.
Process explorer can be invaluable tool for tracking things down...
Process Explorer

There seems to be an issue with one of the svchost.exe's that are running. The one in question was connected to Windows auto update. After canceling it, I could go on the Windows update site. I'm not sure if it's connected, but Add/Remove files works too.

I forgot to mention that MSN Messenger also has a problem. After I enter my password and sign in, right after the little animation MSN Messenger freezes and I have to kill it with Task Manager.

I'll try to find out what's connected to MSN Messenger and see what's causing the issue. I also reinstalled MSN Messenger.

Oh I love it when someone brings something that I can look up.
ih8bills is right .But if you need to find out what all the svchost.exe mean for this can run on XP or Vixta .Go to howtogeek.com there is more about this there.
I found that I removed the worng ones.