hi guys, i've recently upgrade my mac pro 4.1 2009 to 5.1 and upgrade the cpu to 6 core x5690, but it wont start up, when i power it one, it make silence for little while then with all fans on maxi speed with noise, nothing on the screen, i saw on the corner up left on the mother board, just under the first hdd caddy, a red light is on with marque 'cupb' on right, i've tried the cpu board with ram on other mac pro 2009, they worked just fine, not a clue if the cpu has no problem, why the cpu light on? where is the problem? i'm stuck, please help!!! many thanks
