Then why did you download a keygen, anyway? You should have tried the open-source 7-Zip Archiver rather than fumbling with warez... Anyway, try sending the suspected exe (the keygen for one) to Virus Total. If it has viruses on it, then the crack is the one messing your PC.
The following files may be infected:
O4 - HKLM\..\Run: [lphcnoaj0etd5] C:\WINDOWS\system32\lphcnoaj0etd5.exe
O4 - HKLM\..\Run: [sMrhcjoaj0etd5] C:\Program Files\rhcjoaj0etd5\rhcjoaj0etd5.exe
C:\Documents and Settings\__ELONEX__\Application Data\Microsoft\dtsc\32732.exe
C:\Documents and Settings\All Users\Application Data\ankhqfar\opelyryz.exe
C:\DOCUME~1\__ELON~1\LOCALS~1\Temp\jkwhy7.exe
I suggest that you download and install ComboFix (Google it), run it, preferably in Safe Mode (although I often run it in normal), and then let it do the job. God Bless and I hope that you solve your virus problem...