Options > Mail options > General tab > Under send and receive messages make sure there is a tick marl next to "Check for new messages every" and then select how long you want the interval to be in minutes
Then click on apply and then OK > re-start mail client

Is one PC connecting by imap and the other by pop3?
Is one PC connecting by imap and the other by pop3?
Hi Dale, I have now opened on my new pc my AOL mail through IE, and this receives this messages instantly. So as they are both working from the same pc, does this not mean there is an issue with the windows app?
Webmail is just a web interface to your ISP mail so yes it will display instantly. It doesn't mean there is an issue with the mail software.
As dale said what protocol are you using, you should've set this when you set the mail program up.