Inspiron 1564 temporary dark hot spot on screen and reduction in brightness

Hi,

After using the laptop for more than a few hours playing any game, a change in screen resolution (for example, when exiting the game to windows) triggers an abnormal display characterised by a reduction in brightness and a dark spot in the bottom region a few centimetres to the right from the centre. The spot gets extremely hot. The display functions normally about 20 minutes after shut down but the spot appears and the screen dims again when the screen resolution is changed. The dimness is not the same as when normally lowering the brightness (for example, when unplugging the ac power). It is similar to lowering the gamma value.

I've looked for days for a solution and I'm thinking it might be an inverter problem. Any help would be appreciated.

Thanks in advance,

SB

Specs:

Dell Inspiron 1564

Win7 64-bit SP1

Intel Core i5 M430 @ 2.27 GHz

4.0 GB RAM

ATI Mobility Radeon HD 4330 (512 MB Dedicated VRAM)