well it cant help that your using a dell but what exactly have you tried using to fix it so far aside from striking keys and shutting it down?

I haven't tried anything else; don't have a clue.

There is most likly a really simple solution to it but i dont know that so if anyone else knows how then by all means say. However one thing you could try doing is going into control panel from the start menu clicking system and doing a restore back to the previous day and see if that makes any difference.

Thanks for the suggestion; I did think of that, but (and I should have mentioned this) I can't control the cursor; it just doesn't follow the mouse's movements.

Is the keyboard still working if so then try using that to get to it. As well as you have to rember that your screen is rotated 90 degrees so the movement is going to be different to what it would normally be so instead of moving the mouse up to go up the screen it will be sideways and instead of going sideways it will go up and down

Good news and bad news; by standing the computer on end I was better able to direct the cursor, but the machine refuses to be restored to an earlier point.

What kind of video card do you have? I know NVIDIA offers NVRotate, which allows you to rotate the screen (believe it or not, they have monitors that can be rotated, I guess it helps in graphic design or some crap, and this allows you to make your monitor longer or taller or whatever you want, and still keep things normal looking). If you use ATI, I'm sure there is a tool that does this too.... as far as I know, windows doesn't do this on it's own (though I could be wrong)

As far as i have seen with my ATI you cant do that but its not a bad idea going into properties and having a look to see if there are any setting that can be changed to make it better or even using the controller in the taskbar if you have one for your GC there

try this:
ctrl+ alt + up button - rotate to the original state
ctrl+ alt + down button - rotate 180
ctrl+ alt + left button - rotate 90 to left
ctrl+ alt + right button - rotate 90 to right