I have sony dvd rw aw - g170a but this drive is not working ...

The yellow exclamation point is telling you there is a problem with the device. First thing to do is uninstall the device using your hardware or device manager. Reboot. Your pc should automatically recognize the device on reboot and install the proper drivers. If not then you will have to go to the Sony website and download & install the drivers manually. If this does not fix the problem then your drive has went bad & will need replaced. Good luck & I hope this helps you out.