Windows XP in a loop

I have a dual boot setup W2K and Windows XP Pro on different drives,after loading Graphics programs on a third partition and rebooting computer to complete install,when restarted it will reboot before loading XP screen,it will continue in a loop of restarting after each ,XP is the second OS in the boot menu.
When selected from boot menu it will start to load then reboot
Any ideas what could be causing this?

Thanks in advance