I've got TDS-3 Professional and it has detected the Worm.Korgo in my Registry, i.e., HKEY_Local_MAchine\Software\Microsoft\Windows\CurrentVersion\Run[Update Service=winu32.exe].
The 'winu32.exe' is the infected regvalue.
Now I've tried all sorts of removal tools, Stinger, FixKorgo, AVG and some others, but they don't detect it.
So can I just delete the entry 'winu32.exe' which would mean deleting the "update service". ? If I create a restore point and then delete that value, could it be restored later? or would it be deleted permanently?
Thanks.

Go here and read the instructions...

http://www.bitdefender.com/html/virusinfo.php?menu_id=1&v_id=276

Modo vincis modo vinceris

What may have happened is that the removal tools sometimes overlook *one* trace even though they kill the main process and program files. As long as that trace exists the AVGs will detect it, though.

If you back up your registry before you delete this you won't risk anything. If you delete it, everything works, and the entry doesn't reappear you're most likely OK. Rerun your AVG and see if it still detects the virus.