it wont fit because it's lga 775 which means it only has 775 pin holes for the processor, if you go with the intel core i5 it has 1156 pins. they wont line up and you will end up damaging the processor if trying to force it in.
the amd wont fit because it has 938 pins and has a different pin pattern than intel uses.
there are other problems that will arise with such setup as well. the bios isn't programmed for amd, or the new core i series architecture.
basically unless you upgrade to another socket lga 775 cpu it wont have the correct architecture nor will it have the right pin count.
there are cpu's you could upgrade to that will fit in your socket just not any of the core i series or any AMD series cpu's.
the core 2 quad series will fit in the socket that your motherboard is
http://www.newegg.com/Product/Produc...rder=BESTMATCH
this is the series that you can upgrade to if you choose not to upgrade your motherboard.