I have checked everything. Is there any way to reset by usb?
Simple answer, no!
You have not said what is flashing. power, disks, network or all of them. Without knowing this it is very hard to try and help you. When you tested the power supply did you set the Amps load to 3 Amps and if so what was the voltage drop from the no load value?
Another thing, do you have a tested backup of your data?