Possible fault in motherboard for no signal to monitor.

[lepden]

Ok. This is not about a single computer, I've come across a number of cases with the same syndrome and so far ended up replacing the motherboard. Usually this is fixed with re-seating the ram stick, but after trying all possible troubleshooting if it's not fixed then it's either the processor or motherboard. My question is, can a failed CPU result in "no signal" on the monitor? If it's the motherboard fault which components should I be looking for a fault?