Boot Camp - Win7 install won't boot from a USB

[PKBeam]

Mid '07 MB, 10.7.5. SuperDrive is stuffed so I changed info.plist to allow USB install media creation. I created a USB Win7 install via Boot Camp but when my laptop restarts after partition I get the Apple logo flashing with the prohibitory sign and occasionally the question mark folder.

Install USB doesnt show on option boot, rEFIt wont work either. will Win7 just not boot from USB?

 

[DeltaMac]

Changing the .plist does not change your actual hardware, unfortunately.
Windows expects to install from an optical drive, if one exists - even if it is faulty.
Your USB install should work, but you may need to disconnect the internal ribbon for the DVD drive.

I do suspect that your USB "bootable" installer is just not bootable, and incorrectly created.
You SHOULD see it on Option boot, and I would expect that rEFIt should show it as a choice, too, if it was a proper bootable partition.
So, be sure that you are following the directions to properly create the bootable .iso on your USB.
https://support.apple.com/en-us/HT205016

This thread may be helpful for you, too.

 

[PKBeam]

I ended up replacing the SuperDrive.
Windows 7 is now running perfectly, so I conclude that actually trying to boot from an external drive was the problem.