Arduino Uno not Recognized by win7

This was perfectly working on two computers earlier. I soldered my Arduino nano along with a couple components onto a PCB today and wired everything up and when i plugged it into my desktop, windows 7 said that the USB device is not working and something may have "malfunctioned"
I then plugged it into my laptop and loaded the blink sample program and a couple different versions with different delay times and everything was working perfectly.
After that, i switched to my desktop again and reloaded the original program that i was gonna run on it and it printed one line in the serial monitor (it is supposed to give out a continuous signal from a sensor but this time it only printed "setup" which could mean that it did not receive a signal)

now when i plug it in to any computer, and no matter how i reset it, the device is always unrecognized. Could it be that my arduino is broken?

the Blue PWR led is still on when you plug it in and both the TX and RX led flash once or twice