Our sony vaio laptop is only about a year or so old (Windows 7 + Google Chrome). When it's turned on it works great but last week it started quickly fading the display / screen to black when being used normally - typing or using cursor control etc . Moving the cursor (which is not visible when screen is black) or stopping typing for a second, then pressing any key again, brings the display back up to normal. The only other effect is if typing, mostly (but not always) it doesn't display the letters typed when the screen is black. Sometimes it will be ok for maybe 10 seconds before fading, at others it will fade black within a second of getting back to normal It has been alright for a week - seemed to cure itself - but started doing it again today. Today a couple of times, as it went black there was a very quick flash of a white band about 25mm wide right across the bottom of the screen Thought it was a separate problem but maybe linked? When display was ok, it would start then stop displaying letters while was typing. Very infuriating. Does the all the above with the charger plugged in & on battery power only. Nothing to do with any of the F keys. HELP!! Well, despite thinking I had the solution hence me answering my own post... Fully charged battery, mains plugged in or not. It is still doing it! the bloody laptop is almost unuseable.
Maybe answering my own question here; I suspect this is due to low battery. Despite showing over 50% charge it struggles to run screen, wireless etc from that level, even when initially plugging mains charger in. Took a long time to stabilise, while I was attempting to use it. I would expect the mains power to run it ok regardless of lowish battery. It ran fine after maybe an hour of charging. Maybe battery was at a lower charge than status manager was showing Is this is indicating another problem?