What shows in Task Manager (Crtl + Alt + Del ), there should be 4 processes, 3 start with ash..... and one asw..... if there aren't 4.
I would suggest that you try a repair of avast. Add Remove programs, avast! Anti-Virus, Change/Remove button and scroll down to Repair, click next and follow. You need to be on-line to do this.
If that doesn't work uninstall, boot, install, boot.