That's usually a worm....read here:
http://www.gnutellaforums.com/showthread.php?t=41432

If the suggestions made in this thread do not solve your problem, try to open your task manager (crlt&alt + delete -one time), there you go to processes and look for a limewire.exe process. If found force it to end.

Then use the search function of your computer to look for any remaining LW files using the search query "limewire". Delete all those file found.
Then open your regedit via Run...>Regedit. Go to local machines and look for the Limewire folder. Delete it.

That should it be...

Cheers

__________________

"Never Argue With An Idiot. They Will Drag You Down To Their Level, Then Beat You With Experience"

I almost get everything you said. Near the end, I get a little confused..so can you explain to me in teenage language??

Okay, the last step:

Look at the left bottom corner of your desktop. There is a button saying "START". Click it. Now look for "Run...". Click it. Now type "regedit" into it and click "OK". A window will open. There you go to "Local Machine". Look for the folder "Software". Open it. Then look for the folder "Limwire". Right click the folder and delete it.
That's it.

__________________

"Never Argue With An Idiot. They Will Drag You Down To Their Level, Then Beat You With Experience"