What do you mean by " I am unable to make any changes to the MBR", how and what changes?
have you tried booting form a cd and installing an OS? what happens?
enter the bios recovery mode by moving the jumper. look at the manual and techspec for details.
there you will find the option to enable/disable write protection.
By " I am unable to make any changes to the MBR" I mean just that. I went to install BootIT NG and it fails. I used fdisk /mbr and it failed. I ran zap (IBM's old utility for wiping out the first 63 sectors of the hard drive) and it failed (reported write protected).
What is odd, though, is that I was able to use the XP installer to delete the partition that was on the disk. I haven't tried installing XP (I didn't want to waste my time if it was not going to be bootable).
The BIOS jumper took care of it it. I wasn't aware that Intel boards had "hidden" BIOS options like that.