I have a HP right now that came with a X2-4200. I swapped it out for a X2-6000 and everything runs OK just the same issue you have (CPU not recognized). Been almost a year now and have not had any problems. Should not be an issue with a Gateway either, I have modded many a Gateway. There is a possibility that you can find another motherboard with similar specs, you can try flashing the BIOS into your mobo. Back up yer BIOS fiirst, or get a backup BIOS chip from http://biosman.com/. My opinion is that its not worth all the effort. Just get a better Motherboard. Also, be sure to replace that POS PSU that came with the Gateway.