The GT 20L looks to be an LG DVD player. Drivers for any computer you can get from the computer vendor support site, plug in your model in the search, select your operating system.
You may want to start at the beginning and give some details about the issue. Is your optical drive not showing up in the system? Did you try reseating it? When did the issue start? Often you need to clear some registry settings (look up lower and upper filters) to get the drive working if it stopped for no apparent reason.