I have a Gateway M465-E laptop currently running fine with a T2300E Core Duo installed. I wanted to upgrade it to a Core 2 Duo. My brother has the same model laptop and that took a Core 2 Duo (T7200) just fine. Picked up a T7200 on ebay and installed it. Normally when booting all the indicator lights flash once and the fan spins up before the machine actually starts to POST. With the T7200 installed all the lights flash and the fan spins up, but the module bay activity light flashes 12 times repeatedly. I'm assuming this is an error code, but can find no information about it. There are no beep codes. I've removed the ram, HD, Bay module and no change. Switched back to the T2300E and everything works fine. Anyone know what that error code is? The motherboard was actually manufactured by Foxconn if that helps. Update 1 Returned the CPU as defective. I tested it in 3 M465-E's and all of them did exactly the same thing. I still have no idea what the error code is. I'd still like to know for future reference. Perhaps I should try removing the CPU from one of them and see what happens.