Hello I need help.

My company switched from old 3D software (I dont know policy so I wont name it) to solidworks 2015... Also we have get new computers and windows (8.1).

I have problem with selecting edges. To be clear at start its not filters. When I put mouse on edge its not highlighted and I cant select it. But if i move mouse away from edge (pretty away, couple millimeters) its highlighted and I cant select it. This occurs differently sometimes. Sometimes i need to move mouse a little, sometimes a lot from edge to to select it. This is frustrating and slows down my work a lot.

This start happening a few months ago. I tried to work on old 3D software we were using and its same. Same problem with selecting edges... Increasing quality on both software's doesnt change nothing... That means problem is somewhere with computer. Graphic card we use is Quadro K620. I update it to latest version, but no help, same problem. Do someone know what is problem and have solution for this?