can't change resolution, screen cuts off please help

[hotpinkflamingo]

Hello,
I just upgraded and I'm about to hurl my computer. The only thing that shows on all screens (boot, desktop...) is a horizontal strip across the screen that takes up about 1/3 of the height. The actual resolution looks to be huge. I can only see part of the top deskbar, and none of the bottom. The screen resolution link in the admin menu is past where it cuts off, so I can't see it to click on it. How can I fix the resolution? I searched a bit and someone said to reconfigure xorg in the terminal, but I just can't SEE enough to be able to do anything. (I'm not on the problem PC right now.) What can I do? Someone please help.

[hotpinkflamingo]

OK, just for the heck of it I sent into the boot menu and selected to boot from the recovery option. I found a setting to try and restore something to do with the screen. I selected that, and now everything looks right until I log into Ubuntu. Then I get a nice blank white screen.
It's odd, because it seems that the white is just "covering" the desktop. If I click around I can see that I'm moving things around and opening things because I can see the cursor. Just can't see anything else.

[spec456]

Are you using compiz ?

[hotpinkflamingo]

I'm not sure what Compiz is, so I guess I'm probably not using it.
I've managed to fix my problem somehow just now. I booted into recovery mode again, and the last time it loaded the desktop properly. I went into the resolution settings and messed with them. Then when I rebooted into the regular desktop, everything was working.
I really have no idea why I was having the problem, or how it was resolved...
Thanks for your reply, though.