PC Crashed. Now fixed. But won't shut down

[webmaker]

My PC with XP Pro crashed; I guess registry, as I had to use the install disk to get to the DOS prompt and change a file in the WINDOWS\SYSTEM32\CONFIG directory,, I think the "system" file.  I lost many things.  But the machine now works again.

My problem is that the machine will not shut down or restart.  What I now do is to go to the "task manager" and "disconnect" the user, then shut down the machine.

What might be the problem?  And how to resolve?

Thank you!

[Metaphorically]

What kind of a change was it? Did you edit a text file, delete something... ? if you're experimenting, you might want to try closing all programs first, then shutting down. Assuming that doesn't do it, try killing any process in the task manager that have your name under User Name before you shut down. Older versions of Windows used to get hung up when a process did not want to quit so that windows could shutdown. I've seen XP take a long time (minutes even) to shut down, so make sure you wait. What else happens when you tell it to log off or shut down?

[webmaker]

Originally posted by Metaphorically What kind of a change was it? Did you edit a text file, delete something... ?

I don't know what happened.  One morning XP would not boot up and I received a message.  I investigated the message and it said something about the Reg being bad.  So I had to use the XP disk to get to a DOS prompt and move a SYSTEM file from some WINDOWS sub-directory to the CONFIG directory.  Once the new SYSTEM file was installed things worked again, meaning it would boot up, but it was like the computer was a year ago.

So now it won't shut down.