Mail problem

[jhu2]

So I've been using mail ever since I installed leopard and recently its been really weird. Sometimes when I get a new message, instead of showing me the new letter, it will pull something from before. Then to actually read the new letter, I would actually have to go online into my mailbox and read it. I tried restarting the program and it does it again. Even when I try to reply to the original sender, I sent it to the sender of old letter, that mail showed me. Any one know what's up?

The mail server I'm using is my school server, and I'm using an IMAP server.

 

[brainwave89]

How about deleting the com.apple.mail.plist file in /Library/Preferences?
I did that for my gmail (pop3) account and everything came back that was previously there after I recreated the account.
Someone else may want to confirm that all your information will come back with an IMAP account.