Need to turn off firewall in Panda

Hi everyone. Not sure yet where to post such as this, so I'll drop it in here and hope to get a response.

Three months ago I installed a copy of Panda Internet Security 2007 and at the same time had a WiFi modem installed. Everything worked fine up to yesterday, but now something has gone wrong. Each time i boot up my PC and want to log on to the Internet (using Internet Explorer and Google.com start page), I get a failed connection message. If I go to Panda and turn off my firewall, I can then connect to the Internet and Google. I then have to turn my firewall on again and everything works fine. Can anyone tell me what is going on?

Thanks in advance.

M56