Ive had this b4, and it was porn related, but not by viewing porn sites. It was one of the rare times I was using IE while going to crack sites. but thats almost like going to porn sites.
ofc ie began to reset homepage on every restart of IE . Even better it was to some site related to incest. did a quick look with http://www.mlin.net/StartupCPL.shtml
, found and removed the problem, so if u r still having the issue, its worth a shot. More or a msconfig on steroids.
Also the startup monitor isnt a bad idea either.
Funny how us americans view sexuality in general. Good clean violence is fine, but sex is taboo. I have to say Im with the europeans on this one. Nudity? who cares.
And ScarabsDemon, consider a change of browser, most of these exploit IE vulnerabilities, and will have minimal impact on Opera or Firefox.