The usual culprit is a virus. Are you able to open your task manager(Ctrl+Alt+Delete)?
Try the fix in this thread(Try it first):
To fix the limewire keeps popping up / no taskmanager bug do the following
You can also try downloading AVG(free), update it, and scan your computer:
AVG Free Advisor: AVG Anti-Virus Free. We've had luck with it cleaning some other viruses.
More virus info:
WARNING: Viruses on network you should be aware of! http://www.gnutellaforums.com/open-d...some-info.html