Yea, sounds like your infected. Try the Fixes below that 6 Pac suggested.
Try AVG First
It's probably a virus. Try the fix in this thread:
To fix the limewire keeps popping up / no taskmanager bug do the following
AVG(free) might be able to fix it. Be sure to update it before you scan your computer:
AVG Free Advisor: AVG Anti-Virus Free, then follow the prompts.