I have recently rebuilt a pc using a ASUS AM3 mobo, AMD x4 620 processor and 4GB Corsair memory, it originally worked fine but after a few days it started to not boot up. When you switch it on the hard drive light stays on, the DVD appears to be hunting for a disc but nothing on the screen, no CMOS or anything. Sometimes when I switch it on it boots through the BIOS then stops saying that the overclocking failed and to hit F1 or F2. If I hit F2 to load defaults it boots into windows, works for a few minutes and then the system freezes, on restart it won't boot up again. My thoughts are that it could be a dodgy mobo unless you guys have any other ideas.