If trying Melodi's suggestion didn't work and assuming you're running Norton Anti-Virus' full time protection, trying disabling it and then sending a test message. NAV's email scanning feature can create the problems you're having. If turning off NAV fixes things, poke around in its options to see what needs to be reconfigured.
If NAV is not the problem, compose a test message and then turn off XP's firewall long enough to try sending it. If that works, then you'll have identified the culprit and need to download one of the free firewalls...Sygate or Zone Alarm. (I've had no problems running Sygate's free firewall on XP. Others run Zone Alarm successfully on XP but I've had problems with that combination.)
If NAV is not the problem, compose a test message and then turn off XP's firewall long enough to try sending it. If that works, then you'll have identified the culprit and need to download one of the free firewalls...Sygate or Zone Alarm. (I've had no problems running Sygate's free firewall on XP. Others run Zone Alarm successfully on XP but I've had problems with that combination.)
