I have IE, Chrome, Firefox and Opera installed and I use them all frequently. Flash works just fine in the first two, but in Firefox and Opera I get either a black, white, or green box along with the audio on YouTube.

I've tried uninstalling, rebooting, and reinstalling Flash - but the problem remains.

Windows 7 Professional

Intel laptop with AMD Radeon graphics built into the motherboard.

I would appreciate any help to resolve this.