A simple CPU Upgrade???

I have a customer that is upgrading his CPU. He has a Celeron 400MHz, and is moving to a Celeron 733Mhz. Problem: He does not have his motherboard manual. He also has no other material that would identify the maker of his board, so I can’t go out and download a manual. I have no way of knowing which jumpers will need to be changed in order to support the new CPU. Is there a common setting for these changes? Or, is it (as I suspect) dependent upon the motherboard? I tried to install the CPU without changing a jumper, but that did not work. Any help would be apprciated.