you can get a passive cooler for any prosessor ever made.

You can but we're talking about CPU that HAS A FAN INSTALLED and that fan SPINS AND STOPS.

A friend has said to replace the fan before the motherboard.. any ideas on that?

Been getting alot of these machines in T2685 emachine with bad motherboards. first thing I would do is check the motherboard for any leaked capacitor if there if replaced them, if this isn't the case and the system power on but the fan don't spin replaced the heatsink fan, if system was ran with bad fan. cpu is more the likily gone.

the mobo should have a sensor that shuts the machine off if the processor gets too hot though, so i doubt the cpu would be damaged even if the fan was just bad. with the fan not spinning up it is likely the motherboard or the power supply is bad.

That why I belived it the board because pentuim 4 have thermal protection thet clock down the processor if it over heats. plus gettin alot of these in with bad motherboards and that the fan turn on for 1 sec and turn off.

It does make a lot of sense that it would be the mobo. I always replace the mobo before a cpu anyways, but it is most likely about 90% of the time the mobo not the cpu.