Sleepy when top cover connected?

Hey all,

I have got a very odd issue with my macbook!

History:

Initially it started freezing, I suspected that it was overheating so I disassembled it, cleaned dust, cleared old dry compound and applied new arctic silver. Fired it up and all seemed well.

Now:

After I finished fixing it back together I powered it up and the screen blinked and went off. You can see the display as its booting in certain light, just no back light and then it just enters sleep / stand by as soon as the os has booted.

I thought I had possibly snagged the inverter cable on the way through so I went back in and tested the points. Seemed fine, so I powered it up - without the keyboard (top case) attached and it was fine!.

Put it back together and still no screen light and entering sleep mode non stop. What?! At this point I discovered that if I remove the top cover flex cable there is no problem with the backlight or sleep mode.

So I purchased a new flex cable, went on holiday, came back and installed new flex cable and its exactly the same behaviour.

Here is the run down:

with keyboard flex cable connected: power works, keyboard keys works (testing in the seconds available before it enters sleep mode). Mouse Pad works. Mouse button doesnt seem to work. Power and all other function keys work.

when in sleep mode, removal of the flex cable automatically wakes the macbook up and the screen remains on and lit. USB mouse and Keyboard work fine, can put macbook to sleep and wake it up fine.

disconnection of the lid (reed?) sensor doesnt change anything at all.

I have reset the PRAM and SMC with the boot up hot keys. No difference.

I can't think of what I should be looking for now?

My guess is that a new top case might solve this? But why did it go wrong it the first place I have no idea?.

I cant get my head around "Why does the top case have ANYTHING to do with sleep mode??"

Suggestions? Thanks very much!

Macbook details:

Black Macbook 2,1

Intel Core 2 Duo 2.0ghz

SMC version: 1.13f3

Serial: W8717031WGM

Model: A1181

13" Screen

The flex cable on my laptop is silver, and the keyboard has the number: 613-6695 DD#2 - so I did a search for top cases and there is also a version which has a brown/orange flex cable. Would this top case be compatible too?

Cheers

Chris.