T60 display problem - boot in low resolution pink/blue shade

[dlhk]

I have a T60 2623D7U that has a screen resolution of 1400x1050. The problem I am having is that when I start the laptop it starts up with a really low resolution, probably 640x480, and the colour of the screen sometimes has a pink or blue shade. Sometimes it flickers with white horizontal lines. When Windows XP is loaded, I cannot change the screen resolution and even though it shows that it is 1024x768, it is probably still showing at 640x480. Every once in a while it will actually start up with the correct screen resolution and everything works perfectly, but this only happens very rarely. Any suggestions will be greatly appreciated. Thank you.