Problem with new drivers for NVIDIA GeForce MX-420

I was unable to make a new game run at all, so I contacted the manufacturer and was told that my graphics card drivers were out of date. I downloaded 66.93 from NVIDIA and while a picture was displayed it was so corrupt as to be unviewable, and the same thing now happened with other games. Fortunately I know enough to run System Restore, so I'm back where I was before, but what should I try, please?

version 66.93 is unstable and it crashes windows with blue screen. Install 61.77 which is a stable version

Thanks - I never got the blue screen, but maybe I ctrl/alt/deleted before the games got that far. I'll try the other version and see what happens.

No - no good. I downloaded 61.77 and installed (after setting another restore point of course) and got just the same as before - a horribly corrupt display with the contents just about visible. I tried tinkering with the settings in the NVIDIA menu, but none seemed to help, so I used System Restore again, and I'm back where I was.
Thanks for the suggestion - anything else I might try?