automatically all services stoped and main exe file is missing
When? Just after installing? Are you sure you proper install avast?
Did you boot after installing?
At that time, is there any other antivirus in your system?
i tried to install other antivirus didn;t work
Wow... what are you doing?
If avast is not proper installing, trash was left behing by another antivirus and you're trying to install a third one

Well, the conflic and the problems are on your way...