A while back the computer that runs my instrument platform died. I don’t know what happened but I ended up replacing the internal power supply, motherboard and memory stick to get it working again. The front panel USB board was also dead but I don’t use that so I did not replace it. After repairing the computer everything worked except the computer would not communicate with the Arduino that runs the weather instruments. At first I thought the Arduino was dead also but it would work if plugged into a different computer. A different Arduino not programmed with the weather instrument software would work on the computer. Finally after a lot of digging around in the windows registry and playing with the device manager I got it to work. Here is what I think happened.
When I replaced the motherboard and started the computer windows booted up and found that there were two new serial ports (the ones on the new motherboard) since COM1 and COM2 were assigned to the serial ports on the old motherboard windows assigned COM3 and COM4 to the new ports. Now with the old motherboard the weather Arduino was assigned to COM4 and windows remembering that left the Arduino assigned to COM4 even though COM4 was also assigned to a motherboard port. So when I tried to communicate with the Arduino I was actually trying to talk to the motherboard COM port even though the device manager said COM4 was assigned to the Arduino. Using the device manager application assigning the Arduino to an unused COM port made thing work. I still have windows saying there are 4 motherboard COM ports. There are probably only two. All sorts of deleting registry keys and playing with the device manager have not been able to get rid of the extra ports. I probably should have reinstalled windows when I replaced the motherboard but that requires so much putting thing back together that I will leave it the way it is unless some other problem shows up.
The computer is a really nice little machine I built up with parts from MiniBox. It is small about the size of a 2 inch thick book and uses an Intel Atom processor. It only draws about 15 watts, which is real nice for something that runs 24/7.