Ardunio Mega 2560 disapers

I have Windows 10 pro 64 bit on my PC with an Ardunio Mega 2560, Ramps 1.4 with dual fans running a 3d printer with Marlin firmware and Repetier host software.

My problem is that after some time a day or so the Mega does not communicate any more. It often starts showing up as long time to heat my bed in Repeptier and then after I push emergency stop it goes dead.

I can not find it in Windows on the original computer. I connect it to another and it finds ardunio installs the driver but says that it can not start. This is the second time now. I replaced the first ardunio thinking that it was a faulty card but now I do not believe that they only last a few days.

Help is needed