I have had exactly the same problem. I suspect my PC was infected either while I was updating mcafee security,or foolishly attempting to use a crack for a home recording program. I was using an old version of limewire and my PC crashed so badly it would not boot up. Eventually as a last resort I had to restore using manufacturers discs losing all my data. After recovery I downloaded the latest Limewire version which worked perfectly apart from the fact it kept popping back up after I closed it. This was only after only 4 music and 3 video downloads. I also could not delete or open some of the downloaded files. On startup my new virus protection (Blueyonder PC Guard) found untold infections. These were all exe files hidden amongst a downloaded file, I dont know which. I could not clean any of them even after trying all that Norbies stuff. Having very little to lose I restored again. Everything works Ok now. But i've certainly learned a lesson