I just updated my system today. I changed motherboard but other parts are old. The problem is that after post pass, "F1 to resume" appears and if I press F1, I stuck in cmos. If I exit WITHOUT save, it would fine and window run fine. But I have to do that every tome to boot up. What is the problem?How old is the CMOS battery?it is new Have you TRIED (in this order) clearing the CMOS, and loading BIOS defaults?

You changed the motherboard, all the other parts are as before, and the hard disk has the old Windows install on it? I am surprised it even boots. The chipset drivers would be all wrong, unless the new motherboard is the same or similar model to the old one. usually you have to reinstall Windows after such a major hardware change. This MAY be the cause of your problem, unless I have misunderstood.

ah! sorry for I didn't say that I have already formatted my hard drive and install a new window xp. All is fine and work perfectly well but only the problem is that when every time I boot window, I need to press F1 and bios screen appears and choice "exit without save" to continue window.I ask again,

Quote

Have you tried (in this order) clearing the CMOS, and loading BIOS defaults?

it is new

Did your CMOS battery comes with your motherboard? A CMOS battery cost a few bucks so it wouldn´t hurt if you replace it. Just a suggestion..