T23 Win2K: DVD Express key exchange error; multiple monitors

[anacreon]

T23 on Windows 2000 Professional.

I was trying to play a DVD, the same one that I had played yesterday, and I got the error (paraphrasing): "Key exchange error. Copyright-protection enabled. Click 'OK' to close DVD Express."

I found on some forum someone else who had this problem after playing a homemade DVD. This didn't apply to me.

I tried uninstalling and reinstalling DVD Express, but I got the same problem.

I installed PowerDVD and that worked, but very slowly.

It turns out the problem was this:

I was trying to install multiple monitors (for an expanded desktop) but could only get a mirror image. It turns out that this feature is available without a second video card in Windows 98 and Windows editions after 2000, but for some reason not in Win2000.

After giving that up, I still had this monitor on and displaying the mirror image. I turned it off (in Display Settings) and viola! no more copy-protect key-exchange error.

It didn't seem to me that these things would affect each other. Then again, I don't know much. Anyone know why the multiple monitors would cause the DVD program to fail?

Just FYI, in case someone else hits this wall.