Ubuntu Monitor Resolution fixed at 640x480 61Hz -can't change
I have been using Ubuntu graphically (I am not a programmer) with no problems for the last year or so.
A few days ago at power up (a few days after updating software to latest version --which I always do as soon as updates are available),the screen resolution had changed to the lowest resolution and will not change back via the normal preferences window.
How can I get my computer back????