Ah yes, the lure of scantily clad and/or naked girls dancing across my desktop brings back fond memories of my horny teenage years. I remember downloading and installing an app like that and it turned out to be a big pile of malware and spyware. Back then I was running Win98 and the only solution I was able to find to completely remove all the crap that it installed and clogged my system with was to perform a re-install of Windows. Hopefully, you will not have to go to that extreme...as suggested, download HijackThis and post the logs...