Hi, This is my first time building a PC, bought a low class mobo/cpu(Ahtlon XP 2400+) set to test for my first time and i encountered a problem, my operating system on my HD(old HD from old PC with windows XP PRO installed) doesn't start. I assumed i plugged everything in correctly since the PC enters BIOS when i start and detects all my IDE devices. When i finish setting up BIOS or exit BIOS, the PC restarts and enters BIOS again..the OS in my HD doesn't kick in; the HD works fine, i can hear it spin when i start the PC, why OS doesnt' start? thanks.