Might be a boot loader problem (probably rather than might
) You can boot up with the Mandrake install CD and get to the point where you press Enter to continue or F1 for more options. Press F1 and type rescue. Then when you get to the menu, choose to restore the win boot loader. At that point, make sure you have a Mandrake boot floppy.
From there, I suggest looking into using the win boot loader to boot all of your OS's. There are alot of threads around here on doing that, so I will leave that up to you to search for