Windows XP Home Edition Shut Down

[Tbird]

I am expieriencing problems shutting down my computer both through the start up screen (both shut down and restart) and using the external switch. I have trie to restore to an earlier date which seems to work until reboot when it says that the restore cannot be completed. All other programs seem to work fine. I had recently removed some old programs that I didnt use and trials which had expired, but computer performed fine after this. I am puzzled as to the cause of this glitch.
My virus software couldn't find anything.

Thanks for any advice you may have.