Thanks, Kevin.I had some problem again with PHD2, loosing contact with my camera. Maybe the solution is return to PHD1.
My netbook has problem to run PHD2, BackyardEos and Carte du Ciel,all last version. And ASI cameras have problem with USB connection.
Flat can hide small dust. To big dust, the solution is to clean the lens or sensor.
Well, it's time to clean the main mirror, too ! The weather is bad, perhaps I will do it.