Working on an older Gateway, Celeron 733MHz. No post beeps when I first got it. When hitting power button, PSU fan comes on, there is no case fan/CPU fan, I can hear the HD spin, monitor has a no signal pattern, but seems to shift colors slightly in the pattern when I hit the power button. Have stripped each component one at a time and tried to boot, same thing. 2 sticks of RAM, tried with each one by itself, and swapping slots, no change. Tried mobo in and out of case with same result. Tried with known good PSU of higher wattage, same result. Have purchased a replacement mobo and CPU from a reputable reseller, tried different combinations between the new/old CPU & mobo, no change. My final thought is replacement CPU doa. Anyone have any suggestions? Not sure if I have anyone local that can test these old CPUs. Thanks for any ideas!