Avast internet security firewall?

So the program will not allow me to turn on the firewall. Keeps saying “Unable to start”?

I have tried doing a repair via add remove programs.
I have tried downloading the avastclear program and running it in safe mode and then reinstalling. Same thing happens.
The service is turned off and it won’t start.

Really need some help here for my client.

O/S is win 7 home premium 64bit

Regards,

  • Which version of AIS…??
  • Other security related software installed…??
  • Which AV(s) did you use before avast!..??