Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a 4 year old Compaq c700 laptop running Ubuntu.

The problem is that one day the screen suddenly went dark, but the OS still boots up fine. Then I did not use the laptop for a month. After a month, when I booted the laptop, suddenly the screen was working for few minutes, but then it was gone again.

A hardware engineer told me that it is due to old BIOS setting (laptop takes good 2-3 minutes at BIOS screen before OS loads).

Now I'm really confused. Can problems with the BIOS cause this sort of behaviour?

share|improve this question
If your laptop -with the current BIOS- worked fine before, and you did not change any BIOS settings, then this is unlikely to be the problem. – Hennes Jan 29 '13 at 13:28

It is very likely that the backlight of the laptop screen is broken. They usually are made of CCFL lamps, which have a limited life span. If you can still see the screen content when you hold the screen under a bright light (or point a flashlight in a certain angle at it), then it's definitely the backlight. The BIOS seems to have some problems, too, but most certainly that is not related to the screen not working.

EDIT: One other option I can think of: the laptop might be switched to display it's screen content on an external monitor, so try the Fn+key combination which changes that (maybe Fn+F4 for your model).

share|improve this answer
Good answer! Checking external monitors (as mentioned in your edit) happens more often than you would think! ;) – xstnc Jan 29 '13 at 14:18

I've seen it happen that the cables connecting the screen (or its illumination) get brittle with age and break. Or the connectors could work loose.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.