If it did work once, then it should work again. There is one thing that might stop it from communicating though. USB devices usually configure themselves, which is nice. So if you plug in the USB serial converter into one of your USB ports on your computer, Windows detects it and configures it and then assigns a COM port number to the device, eg. COM2. This all works great and your GPSr communicates with whatever software you are using via COM2 serial port.
BUT!! Here's the problem. You have unplugged your USB - Serial converter and put it away and now you want to use it again. So you plug it in. If you plug the serial to USB converter into a different USB socket from the one you used the first time, Windows will configure the USB to serial converter AS A NEW DEVICE and subsequently assign it a different COM port number, eg COM7. (Windows can choose anything up to COM256, it just depends what mood it's in at that instant). But your GPS software is trying to communicate with your GPSr on COM2 (which now doesn't exist).
So you need to go into Windows Device Manager and check which COM port number Windows has assigned to your USB to serial converter and make sure that the software is set to look at that same COM port, or plug the USB to serial converter into the same USB port you used when the GPSr did work.
I hope this helps you
