What stop error are you getting?
and as was said above, remove all internal cards that are not needed. also try to swap around the RAM in the system as well, taking out sticks and moving slots and so on.
but the bad copy of an OS, well unless you downloaded from the internet i have never seen that and don\'t belive that for a second.
If you tell me what stop error you are getting we can offer up more asstance.