Occasionally your "G Drive" may not show up in Windows Explorer or may generate an error when trying to launch files from it--even after a reboot. The fix is generally fairly simple:
1: Launch Google Drive from the Start Menu. You may be prompted to log into Google Drive. Please login if so. Otherwise, continue to step two.
2: From the System Tray, click on the the Google Drive icon. You should be prompted to login. Please follow the steps to do so.