Why have you started another thread on this subject?
Pleas tick one as resolved and stick with the one thread to avoid confusion.
If you have start page virus that is not detected by AdAware or spybot and you can't change your start page then you have the SVCNUT.EXE virus
You can find it at C:\WINDOWS\system32\svcnut.exe for WINXP or C:\WINNT\system32\svcnut.exe for other systems.
Before deleting file you must open WINDOWS TASK MANAGER CTRL, ALT, and DEL and end SVCNUT.EXE process.
You will get a warning before it will do it but just click yes.
Proceed and erase the svcnut.exe virus. make sure you get rid of it in recycle bin too. That should clear it up, you can then proceed to change your start up page to desired page without problem.