If you can connect to the 'Net with your Gateway you can let Windows7 try and find an updated driver for you.
In the Windows Start Menu search area type in device manager. And you should see the Device Manager under the Control Panel section.
When the Device Manager window opens find your DVD drive in the list.
Right mouse click on the DVD drive and choose Update Driver Software. Then choose Search Automatically.
Your DVD drive not showing up in Device Manager? Under actions choose Scan for Hardware Changes.
If that doesnt find the DVD, chose the Add Legacy Hardware option and see if you can work through that to get your DVD recognized.