you have to have four avast! services:
C:\Program Files\Alwil Software\Avast4\ashServ.exe (avast! antivirus service: resident protection)
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe (avast! Update Service)
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe (avast! Web Scanner service: WebShield provider)
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe (avast! e-Mail Scanner service)
The two first of them should be Automatic loaded and the two last Manually loaded.
Well, if you want a minimun running, please, consider the antivirus protection to be loaded and do not mess it