I never had that problem but it is really hard to say what is the issue and not knowing what mother board it has.
Could be the bios has the cdroms in the list but has the wrong boot order. Meaning the roms are last on the list and the system drive boots up first.
Or the bios has a password.
Here is my thoughts.
Try unplugging the hard drive data cable temporarily and see if it will let you open the bios and or read the the cdroms.
Because with out a system drive it will hang for a few moments till it gives up.
