MBP late '06 CPU throttling problem

Hello, guys!
Inherited an old (late '06) MBP from a family member and the machine has seemed to work flawlessly since I got it, until I decided to do a boot camp install of win 7, so I could play som FO:NV.. When tried to play, the machine was laggy as hell, and when I ran win experience index I noticed the CPU was rated way below what it was supposed to. After some confusion I installed CPU-Z, where I noticed that the CPU was on the lowest throttle setting (977 MHz), even on full load. I have tried all kinds of chipset driver updates etc, as I thought it was a problem in Win 7 (which is unsupported on this machine), but on booting into OSX SL I noticed that its the same situation there. I have tried various apps, like CoolBook, to no avail. The CPU seems to be in good shape, as the temperatures are low and steady, and the stress tests all run well (although on lowest multiplier/voltage)

Any ideas anyone?

EDIT: And by the way:
It also has a faulty battery, at under 150 cycles.. I guess it's too late for return...?

 

Thanks for replies!

@iLog.Genius:
The problem is the same in both Win and OSX: It wont throttle at all. It is stuck at lowest clock speed. In windows I can change power settings, but to no effect. In OSX/CoolBook, all options are grayed out...

@Animalk:
It might be the battery is causing this, but the battery shows in system profile and in windows device manager, only it shows as dead and "in need of service"...

I am just hoping its not the logic board. It is the northbridge that controls speedstep, right? And if so, is the northbridge on the logic board?
Is there any way to manipulate the EFI, in order to disable speedstep at HW -level? (I am assuming the EFI controls the chipset, just as a BIOS would on a PC)

 

The battery is ... strange ...
The machine, both in win and osx, communicates with the battery firmware, so it knows its there, it just holds no charge:

Battery Information:

Model Information:
Manufacturer: Sony
Device name: ASMB012
Pack Lot Code: 0003
PCB Lot Code: 0000
Firmware Version: 102a
Hardware Revision: 0400
Cell Revision: 0303
Charge Information:
Charge remaining (mAh): 0
Fully charged: No
Charging: No
Full charge capacity (mAh): 0
Health Information:
Cycle count: 157
Condition: Replace Now
Battery Installed: Yes
Amperage (mA): 0
Voltage (mV): 7982

It would be interesting to know apples motives for killing your computers performance in such a way, when no battery is present... I have read somewhere that it is for cooling purposes, since the battery's surface helps disperse heat, although this seems strange to me, since the last thing you want to do is to excessively heat a battery... (Apple has the only engineers of all the laptop producers I have bought laptops from, who seem to have an IQ-level over that of a monkey..) Both my compaq and my dell is unable to function without cooling peripherals, due to air-intakes being placed under the laptop.. You know, the side that is blocked by the table) .. My 5000$ dell fried its RAM 5 mnts after I bought it, and my 400$ compaq burns my finger (like in potentially giving you a blister) if I touch the VGA port after long, heavy use...

EDIT:
Heres Apples reasoning, which is retarded:
"If the battery is removed from a MacBook or MacBook Pro, the computer will automatically reduce the processor speed. This prevents the computer from shutting down if it demands more power than the A/C adapter alone can provide."

http://gigaom.com/mobile/run-your-macboo/

It seems like its the battery that is causing this after all, then