Something has taken over my computer

I will try to make a long story short. My problems.... when in IE, if I click on tools, then internet options, I can click any tab there except security, if I click that, it shuts down explorer. I can open game rooms at pogo, but not at MSN or sierra. When I run adaware, it runs fine, but when it is time to quarrantine, it freezes. I can open spybot, but when I tell it to check it shuts down with an illegal operation. When I run spybot in safe mode, it does find, DSO Exploit, and when I tell it to fix, it freezes on me. Then tonight, I come to sit at my computer and there are 4 emails....the first is from myself, and when I open it, all it has is the date and from, but if I hit all headers my second received from says : the carrot. There is the time and such, but no body to the message. The other 3 messages are returned mails system messages, all saying the box is temporarily over quota, and they are to... product1@bellsouth.net, videoimp@bellsouth.net, barblaw@bellsouth.net. My isp is bellsouth.Problem is I did not send any of these 4 messages. Any help anyone can give me would be greatly appreciated.