old e-mail

I just had to change my e-mail account because of my ISP, they told me that all my mail would be forwarded over to my new account, but when I first log onto my Windows account, under my user name it says I have 14 messages under my old e-mail account and I can’t get to them. I contacted my ISP, but they can’t help, they say it has something to do with WinXP Pro. Can someone tell me how I can clear this notice?
Thanks in advance,
Dave