Thanks for the replies...I'll have a look inside the box tonight after work.
The stuff on the improper seating of Intel 775 cpu's stock HSF was found here:
http://forum.pcmech.com/showthread.php?t=121401
By the sounds of things, Intel's been shipping them with installation instructions that miss some important points -- the difficulty in seating the HSF might have something to do with the "Stack Cool" plate on the back of the mobo (which would be rather ironic).
If this is likely the problem, I'll be taking the machine back to the shop to have it checked out -- I don't want to mess with pulling out my mobo if I don't have to.
So it's not likely that the CPU is damaged? I shouldn't hassle the guy that built the system for a new CPU?