MaTiCa
Hmm, I haven't really had the chance to look at this thread yet...
But reading through it now, it could be some sort of wireless interference... If the format doesn't resolve the issue, you can maybe try troubleshooting for EMI (Electromagnetic interference)
I.e. When I used a wireless mouse and keyboard, the receiver could not be placed to close to the monitor (because of the inherent electromagnetic field) without it ceasing to work and needing a reconnect...
So if the problem persists, I suggest switching off all non-essential electronic (and even all electrical) equipment and appliances and seeing if the problem still occurs. One by one, switch them on to see which might be causing the problem.
Also, if you're feeling fit, you could try moving the PC to a different area and see if the problem still occurs...
This is just an idea of what it might be... Always remember that it doesn't only have to be "wireless" components that interfere with wireless signals