Windows 7: Core2Duo utilizing only 1 Core?

My system seems to not use both cores of my Core2Duo Processor...

1. HWMonitor shows only one Core.

2. A gadjet that monitors CPU activity, when I forced a cpu load (registry search) Core1 reached 100% but core2 was not used at all.

3. In my Device Manager I see 2 cores.

4. Taskman shows only one activity window for one core!

Any thoughts? Anyone else noticed that on their system?

I haven't installed anything except for Windows Update-found drivers
Motherboard: ASUS P5LD2X/1333. No chipset drivers manually downloaded. ( I will test it after downloading them, but it's strange how it is now)

Note: I have another PC with ASUS P5GC-MX/1333 and it shows both cores...

Look in msconfig in the boot tab click on advanced options and see how many processors there is. Then check the box and select 2 then ok then check make all boot settings permanent.

That's not the problem but it's in the right place, go to msconfig in the boot tab click on advanced options and tick detect HAL and reboot, that will fix it.

I'm posting from my other PC....

I have 2 cores checked by default in msconfig, that's the first thing I do after an install, but it has to do with how many cores it uses during boot only, not later use in the system.

I checked "DETECT HAL" , and now my PC starts with a black screen only.
I can only see the watermark "For testing purposes only" but not anything else. Dead. Mouse and all respond, but I'm actually locked out. I'll enter repair mode to change bcdedit to "detecthal no" if I can access it and post back. This didn't fix it Locked me out. wtf?

Ok, after doing what I described above, I'm back online.Still 1 core though..

So my PC doesn't want "detecthal" option..why is that?
I'll play around some boot options and post back.

MrGrim, can you give me a reference to what exactly detecthal does? I'll search into it.
Thank you in advance.

OK well that's what worked for me when I had the same problem and it also worked for someone else running Windows 7, so I assumed it would work for you but I guess not, sorry limneos.

No problems, I'm a PC technician, I would find my way out, no worries..

I found this which is your solution:
1 CPU detected in dual core system. -Solution - Vista Forums

Let me try some different boot configs and post back.

Cheers

Yup, that's the correct option.
Sorry or not, you'll get your rep! It worked. It's just that I shouldn't have checked "Number of CPUs". I should have left it unchecked to defaults.

Now it detected my second Core.I can see it utilized.
I'll try now to uncheck it , check 2 cores, and reboot, to see what happens.

Thanks!

/HAL=filename

Enables you to define the actual hardware abstraction layer (HAL) to be loaded at startup. This switch is useful in trying out a different HAL before renaming it to hal.dll. This switch is also useful when you want to try booting between multiprocessor and single processor mode when used in conjunction with the /kernel switch. For example, /HAL=halmps.dll this loads the Halmps.dll in the System32 directory.

That's what I was going to suggest as I just read that too, glad to see you have it working.