Avast detected a Trojan Horse so I did a thorough scan as well as Ewido and Adaware but still have the following problems:
-Internet Explorer sometimes won’t open completely and gets hung up "detecting proxy settings.
-The taskbar freezes and is partly blank.
-Have to shutdown using Ctrl Alt Delete when the task bar is frozen.
-Computer will not shutdown, hangs up at “Windows is logging off”.
Avast detected “Trojan Horse WIN32-VB-YN [trj]” and yes, it infected C:\windows\system32\cahyqprp.exe[upx] and C:\systemvolumeinformation..[upx] as well as ewido finding several medium risk spyware. The odd thing is, the problem appears to have no consistency. At this moment, everything seems normal but Internet Explorer and all the problems associated can freeze up without notice as mentioned before.
Also, while infected, I couldn’t boot up and the error message said unable to find Windows\config\sys but after several tries, it finally did boot up.
The trojan does not apparently re-appear after reboot.
I did exactly as you advised and immediately noticed a difference after using cleanup. Shutdown and reboot were all normal. I did the rest as per your instructions and all came up clean. I routinely clear out my temporary internet files under internet options but I suppose clean up must do something more?