First, we need to confirm whether you have the driver installed or not, please follow the instructions below:
To check if you have it installed, do this by going to Control Panel > Programs. Scroll down the list of the programs and verify if you see the PL2303 USB-to-Serial. If it's installed, highlight the said program and click Uninstall. Once the driver is removed, turn off your computer and wait for a few minutes. Power up your computer and download this driver: (
http://www.usglobalsat.com/store/download/590/windows_allinone_usb_driver_v130.zip). Make sure to extract the file first before installing the driver.
If the driver is not in the list of Programs, just directly download the driver.
Plug in the device with the provided extension cable and check the Device Manager. You can do this by right-clicking on Computer > Manage > Computer Management > System Tools > Device Manager > Ports (COM & LPT) > Prolific to USB Serial Comm Port (COMXX).
To test your device, please download the ND-100S GPS Test Utility: (
http://www.usglobalsat.com/store/download/590/nd-100_gps_test_setup.zip). Open it up and extract it. Bring your computer outside where there is clear access to the sky and there are no tall buildings or trees around that area.
In the said utility, select the correct com port, choose the appropriate baud rate, and press the Connect button. You should see some scrolling data on the Terminal window. Also, check if the blue light is blinking.
Let me know how it goes.