First you shouldnt be on porn or warez sites. lol. But seriously what Antivirus protecting do you have? I had similar problem as you. I got so frustrated i just reformated it. If your using one try a different one. Also does it tell you where that file is at? If so go in safe mode and delete that file. If that file is really important ask someone for copy of that exact file if it went into your system files.
I used AVG free version and found if found Backdoor.Coreflood trojan horse. It found the trojan horse but had exact problem as you. It just wouldnt go away. So like said before just reformat it or get new antivirus software. After i reformated my computer i went and bought Norton Antivirus and havent got trojan horse ever again(probably also the fact i dont use Kazaa anymore.)
Fresh from a reboot, kill all processes related to Rundll32.exe.
Delete the friggin file. It's usually in the temp directory somewhere.
If the adware/spyware doesn't have any other hold in your system, this should work. It's a known variant of the Startpage family. You get it from lots of sources, like unscrupulous freeware sites (usually the ad supported ones). Yeah, and underground (read: illegal) sources.