Start with http://support.microsoft.com/default.aspx?scid=%2Fsupport%2FIE%2Fie5%2Ftopics%2FPCBD.asp
Or contact aol tech help.
The most likely cause, if it suddenly started, could be some virus of other malware. That might be difficult to find and remove if you can't connect to the Internet.
Good luck.
Kees
I'm running XP home on an hp pavilion. I have aol and all of a sudden I can't access any web page. I've re installed aol, tried to reinstall IE 6 with a cd, and don't know what else to look for. Help!

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic