You buy a used Intel Core 2 Quad Q9650. You install it. The system powers on but shows a black screen. The original manual says nothing about being required, nor does it mention TDP limits (95W max – the Q9650 is 95W, but the VRM on the board might throttle).
Ensure you are running at least 4GB of DDR2. Some users have reported success with 8GB (2x4GB sticks), but this is chipset-dependent and may require a specific patched BIOS. acer mcp73tad motherboard manual patched
The correct patched .ROM or .BIN file matching your specific motherboard revision. You buy a used Intel Core 2 Quad Q9650