Also for further information: In the last few days I had the opportunity to test the following distros, some of which also gave problems with screen display on the same machine:

Peppermint 4
Ubuntu 12.04 screen also deteriorates, no solution found
Bodhi 2.4
Slax 7.0.8
Porteus 2.1 screen also deteriorates, still trying to resolve it

I think my best solution is to get another laptop without nVidia card