Intel P4 Mobo Won't Boot XP HD?

I just replaced my Intel P3 mobo with an Intel P4 mobo (D845PESV). I had 2 hard drives in the case before, one was an old 10GB with Win98SE on it, and the other was my boot drive with Win XP on it (master). But even though the board fires up nicely and gives me the satsifying Intel P4 logo screen, it won't boot up to the hard drive with XP on it. If I hook both drives up as it was set up before, it tries to boot to the win 98SE disk only. Is there something that I am not doing? Why won't it boot to my XP disk (WITH ALL MY STUFF ON IT)?

Thanks.

Ken

I tried that. It doesn't work. Changing the Mobo changes all the little settings, you know those DMA, IRQ, memory location type of things. Maybe there's a way to change Mobo and keep the same HD but I could never figure it out. I had to reinstall the O/S. Did you get a "you've changed the hardware" error?

You will have to repair windows xp, because when a mobo is changed windows xp will block access to it by restarting your pc countinously you will have to boot from the windows xp cd and re-install windows, whcih mobo do you have , if its powered or built by SIS or ECS you will have problems