how long have you had this problem?
i acutally have this problem on my other computer and i know whats wrong with it, but 1. i dont know how to fix it (well i kinda do), 2. too lazy to fix it.
did you by any chance, go to tweakxp and run that file that gets you rid of msn messanger? If you did, thats your problem, becuase hotmail now loads msn messanger, so if you deleted it, when you go to your inbox hotmail first searches for msn messanger, and when it cant find it, its gonna take a long time to load hotmail.
Best chance at fixing this (if you dont want to reinstall windows, or at least the msn messanger), is to use outlook express.