Screen completely disappears while working on battery

[Van GORRE]

Problem description:
While working on the battery (original) without being connected to outlet , it happens that the screen in laptop 'switches' both up/down. After a second it returns to 'normal' position. Sometimes it also happens that the screen completely disappears and the background turns into one colour (random colours). At this point I have to use the key combination FN+F7 to switch the screen between VGA and LCD screen. After that, again, everything returns to 'normal' position.
Addtional info: I've exchanged the CPU. The former was T2300E, now it's T5500.

All in all, my question is: what makes the screen to 'behave' in such a 'freakishly' way?

Thank you in advance for any solutions to my problem...

[beGi]

I had similar problem with my screen when working on battery, screen would start to flicker, turn off and change color. Updating video drivers made all that dissapear... Hope it helps...

[Van GORRE]

You made automatic update by Think Vantage / Think Pad "system update" or download new driver form intel site?

[beGi]

I downloaded it manually from Lenovo site.....