Which component is more important: the motherboard or the CPU?
Which component is more important: the motherboard or the CPU?
I'm dealing with a tricky situation fixing your friend's Dell Precision T1650. It kept looping and showed memory errors through LED signals. When you swapped out the RAM, it still had issues, even with different modules. After removing the CPU and trying it on another motherboard, it booted quickly but didn't recognize the RAM. Using a fresh Windows installation helped, but the Dell board still caused problems. The issue seems to be with the motherboard itself rather than just the CPU. It's possible the board is faulty. I'm hoping your friend can get it working soon for their visit next weekend.
Ensure BIOS is current and disconnect all components except CPU, GPU (if necessary), and one RAM stick. Leave drives off. Since the CPU runs elsewhere, this appears improbable. It's also unlikely you swapped a faulty motherboard with another bad one, though it's possible. Possibly the original unit had issues and the new one just needs an update. Also, attempt to reset CMOS.