There are lots of good boards from many manufacturers. You need to decide if you want to go AMD or Intel, depending mostly on your budget. You may be able to use parts from the system you have now, but you may also end up buying more than a motherboard and cpu, you may need memory too at least. Let us know your budget and your system specs and what you plan to do with your rig.
Is it a laptop? If so, you won't be able to upgrade the processor or motherboard (most likely).