Help! Old man needs computer help

Help Please, if you can!
I use firefox and then try IE6 with the same results. I am also on satellite and use XP!
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My email won't download new mail, Thunderdbird nor Eudora. I can get to webmail.
Once I get to a site it takes forever to fully open. If I stop it and reload, sometimes it will finish.
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I can not download anything, using 'open' nor 'save'.
I have run ad-aware but can't download Ad-Aware SE also spybot.

My anti virus programs can't find anything. I have firewall protection!
I have not downloaded SP2

When I do get online sometimes I get kicked off or loose a particular connection but not all !!!
Direcway says its a hidden something or other it in my puter. [my works]
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How do you find a hidden bug or virus?
McAffee Trenmicro AVG ZoneAlarm has been no help.

Thanks much
charlie