Cant change resolution after reboot

[Wade Smart]

I have a fairly serious problem. Earlier today I decided I wanted to 
monitor the temp of my cpu so I did some research. I installed gdesklets 
and lm-sensors. I ran the detect script and it added what it found to a 
file. I started gdesklets and chose the cpu monitor but it said no 
lm-sensor found. So I thought maybe I had to reboot before it all would 
take effect. But upon reboot I found that my monitor resolution went 
from 1600x1200 to 640x480 and I cant change it. Whats worse, on this 
email that Im typing, after I hit send ill have to turn off Thunderbird 
because I cant seem to shrink any application on the screen to gain 
access back to the desktop. Alt-Tab doesnt seem to work switching apps 
either.

Suggestions would be very helpful right now.

Wade