Hi, I used Debian 7 (amd64 Gnome) in my desktop. Never had an issue.
Yesterdar I installed Debian 8 (amd64 Mate) and constantly my screen becomes unreadable.
In both cases I used the default drivers installed by the system, nouveau.
HP Pavilion a6000n PC, 3G ram, 250G HD
Nvidia Geforce 6150SE nforce 430
I appreciate your help.