I have built and printed a couple of test runs on the mendel90 with no issues whatsoever, until I tried increasing the heat settings for the bed and filament. When manually jogging the Z axis to lower it worked fine, but as soon as a print was loaded into pronterface and began printing, after the z axis had been homed and began lowering, one of the Z axis stepper motors would stop turning (but still buzz) while the other continued working. In my haste (to prevent potential damage to any components caused from one side lowering a lot more than the other, I hit the power switch on the CPU. All worked fine and reset, connected again and tried to solve the z axis motor issue. After the motor issue happening a second time, I hit the switch again to prevent damage. Now upon reloading, the serial port has disappeared entirely and I cannot even find it connected under device manager, even though there is the distinctive 'bing' when the printer is turned on and plugged in. Any help please?