I have Windows XP SP2 and I can't log off, shut down, or restart my computer with the start menu, or CTRL-ALT-Delete. I tried running the exe to shut down but that didn't work. I have both admin and non-admin accounts and they both won't work. To turn off my computer I have to manually hold down the start up button. I'm so clueless. One thing I do suspect is Tune Up i had the free trail and was messing around with it and I think that just effed up my computer. My computer went so haywire after that and I also can't do a system restore. The only thing I can do is lock it.