Screen goes off at random intervals

Hey there,

I have had my laptop (a Toshiba Equium A300D - 16C) for around 5 to 6 years now and have been experiencing recurring problems with it.

Most recently, the problem has been that I will be working away on my laptop, watching videos or playing games etc. (you know, the usual rubbish for a personal laptop) and the screen will either go black, white or come up with coloured lines (I've had all sorts of colours). Unfortunately, the only thing I can do at this point is to turn it off by the main power button and restart, sometimes resulting in a startup repair.

I have read around a little (in between restarting my laptop) and have come across mention of a damaged graphics card. If this is the case, bad luck as it costs almost as much as a brand new laptop to replace.

So far I have tried cleaning up my registry, checking that the graphics card is showing up on the device manager, hoovering the fan (which I do regularly anyway, as it over heats a lot) and un-screwing a few bits and hoovering those out too to get rid of any dust.

I'm not really a computer whiz and am pretty oblivious when it comes to technical terms, so if someone could explain to me what could be going wrong and/or how it could be fixed in layman's terms, I would much appreciate it.

If you need any more information, please let me know.

Many thanks.