Mail not working in Leopard

I hope somebody can give me a few suggestions on how to solve this problem. I've spent the last 3 days trying unsuccessfully to solve it myself.

So, I installed Leopard the other day and I'm starting to regret it. No matter what I do, I cannot receive Mail from my exchange account. I went back and booted in Tiger from my external and it worked fine, so I don't believe it is a server problem. I checked the settings I had in Tiger and made sure they were the same in Leopard. I tried to fiddle with the settings and even tried it as an IMAP account. My subfolders show up in the sidebar, but I never see any of my actual mail. Connection doctor says the connections are fine. What am I doing wrong and what can I do to fix it?

Oh and I also can get my mail just fine through Entourage which I might just have to use from now on. I just liked Mail better.

Any clues? I really don't want to reinstall Leopard if I can avoid it.

Thanks!

 

So nobody has any ideas? I am seriously thinking about going back to Tiger. Maybe then my computer would stop freezing too. I am so unimpressed with Leopard. I can't believe I paid for my computer to lose functionality!