my usb superdrive wont play certain dvds

And your question is????

If the SuperDrive will play a purchased DVD Then it isn't your SuperDrive it is the Rented Media is Junk from being scratched up. Many users have had problems with rental DVD's

Another help source (if you haven't already done so).

Go to your OS Help Menu. In the search field type dvd

Click on all the troubleshooting topics & Support Articles that pertain to your issue.

You can also do the same in Disk Utility. Open same up.

At the bottom left of the window, click on the purple button w/the "?" in the middle.

This will bring up the Help Menu.

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Try a different brand. Top forum favorites

CDs

FUJI

TDK

Verbatim

DVDs

Maxell

Verbatim

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Apple's Disc Burning Quick Assist

http://support.apple.com/kb/HT2801 Apple Portables: Troubleshooting the slot load optical disc drive

Make sure the DVDs are not dirty, smudged and/or scratched.

http://support.apple.com/kb/TS2000Mac doesn't start up from install disc

http://support.apple.com/kb/HT2801Apple Computers: Troubleshooting the slot-loading SuperDrive

*** Your drive may need cleaning. Cleaning kits can be purchased from any store that sells CD/DVDs. ***