occasional black screen

[Guest]

sometimes just after startup the screen goes black for about 2 seconds then
recovers also during use but on nothing specific can anyone tell me why?

 

[Guest]

That's normal during the boot process.

 

[Guest]

Thanks but I didnt explain very well the black screen appears at intervals
just for a couple of seconds, sometimes it doesnt happen at all and then
other times it happens every few minutes. I cant say that it happens when I
am doing anything specific I've tried to take note of what I am doing at the
time but there is no pattern. I just wonder if its doing any harm.