Very Slow Internet performance with Firewall

I changed from Zonealarm Pro to Comodo Firewall, Anti-virus & Mal-ware, works very well, however, my FIOS 5mbs digital service went to a 56kbs dial-up speed and about every other Internet site requested was rejected as not found! Trying again might get the site.

FYI HP M8000 AMD dual processor, 2 GB ram and running at 5GH

I’m open to suggestions.