Gnome Desktop lower quarter blacked out

[snif123]

Hi people,
I had Ubuntu10.04, using inspiron1545 and running on an external monitor,all of a sudden, the lower quarter of the desktop got blacked out,i had no choice but to upgrade to 10.10.Today i closed the laptop lid and now the lower 1/4 of the desktop is blacked out.again.tried restarting,changing monitor configuration but no result.i have put an image to better show,as you can see the lower 1/4 before taskbar is just black. all my compiz settings have gone and login works with no problems and starts gnome then the bottom quarter blacks out 3 seconds later.any ideas cos this is killing my UB experience

[sikander3786]

Please post the outputs of these commands.

lspci | grep VGA
glxinfo | grep Vendor
cat /etc/X11/xorg.conf

And I am just wondering if you get the same blank bottom at your Bios screen or not? I mean you must be pretty sure that the LCD itself is in good health? I've seen some LCD problems like that before.