Loosing E-Mail connectivity in XP

OK has anyone else run into this problem I have a XP SP2 fully patched box collecting incoming e-mail from 5 different sources and periodontally this unit looses the ability to login and collect e-mail. It is free from infection and sitting behind a router and dedicated Nix Server.

The e-mail regularly fails to connect and I need to delete the existing e-mail accounts and reestablish them again and then it works for a couple of months and breaks again. I can collect all E-Mails and then next time I login 6 hours latter be unable to connect to the e-mail collection points.

While the solution is a simple work around it is getting tedious having to reset all the accounts and spam filtering every time this happens.