When I open up wc3 tft, the screen is 'split' in the middle. The right side is on the left, and vice versa. When I move the mouse to the left side of the screen, it comes out on the right side.

What do?

I tried taking a screen shot, but it showed up as though it were normal. I've edited it to show exactly what I see. My mouse cannot get any further than the black bar in the middle, and when I move it all the way to the left side, it comes up in the right side.

It's almost as if your computer think it's running multiple monitors.

What does your computer say under Control Panel\All Control Panel Items\Display\Screen Resolution

Try clicking detect to auto detect your current setup.

Reinstall your active X