Be very wary of viruses. There's recently been a major issue similar to what you explained. See LimeWire continually Popping up every few seconds & also Opening at System Startup & check that folder & your computer with anti-virus program with up to date definitions. Also get these:

1. ad-ware (FREE), 2. Spybot - Search & Destroy (FREE), 3. Peerguardian (FREE)