Freezing problem on my 1645 and Dell wants to replace the motherboard

I've had an ongoing issue with my S-XPS 1645 where everything will randomly freeze. The mouse cursor will stop moving and everything is as if time suddenly stopped. The only thing I can do is hold the power button down for several seconds to force it to power off, then restart it.

I don't see how it can be any software, as the problem has persisted an OS re-installation, and it sometimes freezes even before it has booted up. I ran dell's diagnostics and didn't see any errors. (I had to leave, though, and I left it running since it was taking so long, and when I got back hours later, there were no error messages.)

Dell wants to replace the motherboard and heat sinks because I mentioned that sometimes while it's frozen the fan will start spinning up as if the processor is chugging away at something, and so the rep just latched onto that as something he could call an issue so he could give me a solution and get off the phone.

Anybody have any idea what the real issue might be? How should I handle the tech support guessers? My warranty is up in April, so I'd like to resolve this issue before then...

 

It could be related to the heatsinks due to the fact that if it gets dirty it can cause the system to overheat and lock up. You say it freezes before it boots sometimes, but does it do it after an immediate reboot or has it frozen at boot before while the system has been left off for over half an hour before turning it on again?

Has it frozen during installing Windows?

Does it freeze at all BEFORE you have the drivers installed for your chipset and video?

Simple solution first is to try and clear out your heatsink of any dust or debris. Take it to an air compressor or blower and really hit the fan and where the heat lets out. Heck, I've used a leaf blower on mine before to clean out my heat sinks. Just give that a shot first and see what happens.

If that doesn't work and the problem IS overheating, then you may have to take apart your unit, remove the heatsink, clean off ALL contacts between the heatsink and chips, and then apply fresh new thermal compound. Sometimes that thermal compound inside dries up and becomes useless and needs to have a new application.