I just built my pc with MSI K8N Neo2 Platinum MB , AMD 64 3000, Kingston DDR400 1GB and Coolmax CX-450B 450W power supply. When I use the power button in front I get 1 long beep and nothing happens but if I hit the front button to turn on and then use the power button in back, off then back on again I get 1 short beep and everything is fine. Thanks for your help!