Yes, that is why I said he might have left something out eg didn't tell us something - what you suggest sounds exactly what could have happened
next time select reboot but don't save changes or configure it so it'll try and boot of the dvdrom drive first then the boot harddrive second
I've never had any problems either
All one has to remember if dabbling in reconfigurating ones hardware setup 'expect the unexpected' since alot of people leave well enough alone as long as it works but the trouble is sometimes it still isn't set up properly and when you add that extra device it all doesn't work the way you're expecting it too...
The SAM or UBoot etc has 2 or 3 files that need to be sorted and then once that is all ticked off there's that elusive kickstart directory with the likes of diskboot.config and Kicklayout but generally most people can stay out of there
