alessandro, if you changed your card but your graphic drivers are the same as the old one, you may try like Mr. Abner suggested and delete the entire /cache subfolder under your SpaceEngine installation folder. It may sound dumb, but check also if you inadvertently disabled planets in the filters toolbar to the right.
"Time is illusion. Lunchtime doubly so". Douglas N. Adams
| My mods: http://forum.spaceengine.org/viewtopic.php?f=3&t=80 | My specs: Asus x555ub - cpu i5-6200u, ram 12gb, gpu nvidia geforce 940m 2gb vram |