PC will always crash when Multi Processing is enabled

Here are my PC Specs:

Windows 7 Ultimate,
Toshiba Satellite x200-21T,
Intel Core 2 duo 2.20ghz T7500,
Nvidia 8700m GT

Its been three years since I've been using this laptop but I recently learned that all this time I've been using a single core while my PC actually is dual-core with 2 cores.

I have an option in BIOS for "Multi Processing" which enables the 2nd core. But.....

When I enable it I can't do anything. Windows boots up but after a few minutes I get a bluescreen. The error on Blue Screen is pretty random but most of the time its "IRQL_LESS_OR_NOT_EQUAL" and "0x000007f".

But not just that. When I try to Install Windows or even use the Windows Startup Repair my PC freezes. My PC came with a recovery CD which installs a fresh copy of Windows. It will even freeze if I try to install from that CD.

I've been told that its BIOS problem. I upgraded my BIOS and downgraded it back to its default version. I even downgraded it to an older version than the default one but no luck.

Oh and yea. The only thing that works is Safe Mode. I can see both the cores in Task Manager and the PC stays on without any blue screens.

When MP (Multi Processing) is disabled my PC runs pretty good without any problems. But I really need to enable it because I want to play a game that requires MP.

So I upgraded BIOS, downgraded it, used 3 different Windows CDs (Vista/7), installed XP but none of these worked.

Any ideas?

Thanks in advance.

 

So when you don't enable "multi processing" it only shows one CPU in the task manager?

 

Yes, I see only one processor there.

 

Have you googled this problem?

Have you also tried known good RAM, HDD? Sometimes a bad stick of RAM will cause BSOD.

 

Thanks for your response.

I have another x200 laptop here. I removed the RAM from mine and inserted the RAM from that one but its still the same. I still get BSOD.

 

Check your Device Manager and see what driver the "Computer" is using. It may be that your machine is using a uniprocessor kernel, so it's crashing when you enable your dual-cores in the BIOS. I'm guessing the machine didn't ship with Windows 7, so since you installed it when it only "saw" a single-processor kernel it only selected the single-processor driver. An ACPI multiprocessor driver is what you should need.

 

It came with Vista Home Premium. I can't install it when I have Multi Processing enabled. And when I install it without MP it won't boot if I enable it again.

 

You also could have a bad motherboard/CPU

I would grab another socket P CPU and test it out or rule out the motherboard.

 

If that's the problem then that's it. Screw this laptop. I am getting a new one.

 

I've can remember a simillar therad.. (Same user?) Have you tried to install Windows SeVen or even XP?

 

Yeah, I started that thread.

And yeah, I tried both. I am currently using Windows 7 without MP and it works fine but if I enable it I'll get BSODs all the time.

 

Take the processor from the other X200 and put it in the failing one.

 

Where is the processor located and how to replace it?

 

I believe you have to take off the screen/lid and the top part of the chassis to get to the CPU.