Sounds like windows thinks you have an old crappy monitor installed- even if the drivers are installed, windows might not realize it's hooked up. you should be able to verify it in the display properties window. If all else fails, change it to a generic 19" or 21" display, and that should unlock all the resolutions for you
A lot of monitors are plug 'n play now- did the VGA cable possible jiggle loose?
AXIA T-Bird 1GHz @ 1.30GHz
Pentium IV 2.4C Northwood- M0 stepping @ 3.2GHz HT
Air Cooled w/ SP-94 heatpipe & 92mm Vantex Tornado at 45C
4x256=1gb dual-channel 2-3-3-6 OCZ PC800DRAM @ 890MHz 3-4-4-8
MSI Neo2-PLS w/I865PE & SATA @ 4x267=1068MHz
BFG GeForceFX 5900@485/967MHz = 6284 3DMark2003s; dual-head 21" CRT & 19" LCD