If the "antivirus software" was dowloaded by clicking on an ad that said : "Your system is/may be infected, click here for protection." then you probably just loaded spyware on your computer.
Get Lavasoft's Ad-Aware, Spybot Search and Destroy, and Grisoft's AVG Antivirus and do complete system scans with all three(after checking for updates, of course).

And also check windows update for security patches for your operating system.

Can you get your mail using your normal email client(outlook, eudora, thunderbird, etc.)?
Checking to see if the server is working properly?
It may not be poker tracker.
However, if your email is functioning normally, just not within the pokertracker client, then you know where the settings need to be changed.

I have not used PokerTracker yet, but I do advise people about their computers for a living.
Maybe someone else can speak up here about which configuration settings you need to check.

About Panda Antivirus: after the installation, you need to either configure regularly scheduled file system checks, or enable the autoprotect features.
I would also check for new virus definitions(check for updates), and perform a full system scan at least once a month, but always immediately after getting updates.
Check to see if an email autoprotect feature is enabled, and try disabling it to see if anything changes.