SUPERDRIVE reads ALL my DVD's EXCEPT ONE!!!:: My Windows 7 Home Premium. WHY IS THIS?????

iMac reads all my DVD's except one my WINDOWS 7 HOME PREMIUM INSTALL DVD!

The windows dvd works fine on a pc so I know it's not the DVD.

Now I have seen people posting that their Superdrive doesn't work, or that it only reads cd's - I DONT HAVE THOSE PROBLEMS!

I reiterate my Superdrive reads ALL DVD's EXCEPT MY WINDOWS & HOME PREMIUM INSTALL DVD.

Is the Superdrive designed specifically to reject windows software? Absurd as it sounds this is the only logical conclusion.

This is what i have been trying to do over the last 4 days:

I purchased Windows 7 Home Premium DVD so I can partition my Hard drive and devote 100gb to Windows.

I have a late 2009 iMAC running the latest Mountain Lion OS.

I have cleaned the Superdrive by putting a credit card and microfibre cloth like people have suggested. If it was dirty or required cleaning then surely it wouldn't play any DVD and not just the Windows DVD? anyway that didn't work either.

Since the Superdrive reads the Windows 7 DVD once every 30 or so tries when it is eventually recognised I try to install it via bootcamp. Each attempt windows stops, the first time I got as far as the windows is loading screen and was stuck on that screen for 2 hours and was forced to power off, the second time I got as far as please load a driver or something and press any key with a flashing cursor in the top left of the screen, pressing keys did nothing.

I have tried to install windows via USB like some people have suggested.

I can not boot from my USB.

Some people have said Bootcamp will not allow you to but there is a work-around by going into .info and editing in my iMac version via textedit, which I have done.

Still can't boot from USB.

The USB has been formatted to Mac journal and all windows files copied from DVD to the USB and there is an .iso on the USB also.

Still can't boot from USB.

I have partitioned my Hard drive via Disk Utility but can't find a way to install windows on said partition since it never appears in Startup Disk.

Starting to believe there is a conspiracy here.

Please help.