Macbook Display Problem (A1181)

Hi,
I am hoping someone may be able to help me - i have an old Macbook A1181 which has now got a display error, upon starting the macbook the display is fine for the first minute or so - then it starts developing a scrambled type of image where the screen is so unstable the image is distorted and scrambled - almost like interference..... I have connected it to my hdmi tv using mini dvi adapter and the image is stable on the tv albeit not great quality....

My question is it the screen that needs replacing or is it the logic board ???

I have attached a couple of images so you can see what i mean and any advice greatly appreciated....

Thanks for the advice - there are A1181 1.83ghz logic boards on eBay - is it as easy as taking old one out and replacing with a new one ???
I can't afford a new MacBook so am sad now.

HELP - I have just read an article regarding "reflowing" the gpu !!! Basically cooking the gpu to re set (flow) the solder correctly. There are lots of people that have had success doing this !!! Is it worth me giving it a go - what's the worst that could happen ?!?! I get a broken MacBook ....

Thanks again - are you able to tell me exactly how you cooked it in the oven - its worth a go.....

Well I have cooked my logic board tonight !!! I will put it all back together in the morning and we will see if it works......... #omg

Dream !

Guys thanks for all the advice just thought I would let you know that cooking my logic board to reflow the solder has worked a dream.... The MacBook is alive and screen is perfect. I'm a happy chap.