Frankly, Sportsdude, if you ask me - I would look for some nasty in your computer (or maybe it's in another computer on your network). Not being able to use your mailbox just isn't normal, you shouldn't take this kind of thing.
The easiest solution would be to format your HDD and reinstall your operating system, otherwise you might check for spyware, viruses and trojans.
Online spyware and virus checks at vny!://www.trendmicro.com
Look for online trojan checks with a search engine.
You could also perform a check with Hijack This! which lists all found software in a log, and submit this log to some places on the web which are dedicated for that sort of thing. Look with a search engine.
