Avast Pro 5 /gmail and comcast mail

Hello-
I hope someone can help. I upgraded to Avast pro 5 and since to install i cannot access gmail or comcast mail. Also it is like any links i click on don’t work, for example on the comcast homepage, the weather doesn’t load and the “top stories” links don’t load up. I reinstall IE8 but that did nothing, I also checked flash and shockwave . But this problem occurred after the upgrade. I scanned for virus’, and all clean. HELP!!!

Oh its Win XP, 900 MB RAM, DELL …and GMAIL will work in the "SLOW CONNECTION, HTML SETTING------

Thanks