i just installed a athlon 754 pin in my computer , changed the paste and it didnt start .... fan went on , lights went on but nothing happened on the screen . BUT i did replace my old one with new paste and it works like before .... i did retry again with that athlon and it doesnt work ... i plugged my semphon back ( the original 754 pink cpu i had) and it work as usual... any ideas please Thanks Guillaume St-Pierre