Hi, you have probably without realising downloaded and open a program that has a single "setup.exe", mine was called "a" made by XTC.
I found this in c:/documents and settings/"myname" folder (the name that the folder is called, in most cases your name)
I tried to delete but was told it couldn't be deleted, even though the icon never returned, but still limewire continued to open.

Next I downloaded a programme called "tuneup" and used the "tuneup start up manager", from here deselected a programme called "setup.exe" and this fixed the problem without causing other programmes not to work.

I recommend if you do this you only deselect one at a time, and then reselect it if it does not fix the problem.

Rik