Screen resolution and flicker problems

[audreymac]

I am experiencing the following:

intermittent screen flicker/ colour fading/screen size changes i.e. right hand of the screen margin increases (this is a new problem).
In screen resolution it now only goes to 1024 x768 with a refresh rate of 60 (which is what it is set at NOW) - it was .....x1600, with refresh rates of up to 90.

Is there some conflict or two systems running?
Any help appreciated.

[audreymac]

I booted up in safe mode and ran fix errors - this has fixed the screen flicker/fading colours.
However, the screen resolution is still 60 and now I have a new problem .
Totem Movieplayer will open requested utube video listings but when I try to play one of them I get the following error message:
An error occurred - location not found.

[audreymac]

I reconnected cable at the back of PC monitor and this, for some reason, adjusted the screen resolution settings up to 1600 x1200.
Any comments, please?