One of my PCs has dropped it's display to 800x600 w/ 4 colors-- A7N266-VM mobo

[bupkus]

One of my PCs has dropped it's display to 800x600 w/ 4 colors

It has built in video on it's ASUS A7N266-VM mobo.

I tried downloading new nVidia drivers for the nForce 220D chipset from MS's "Windows Update".
I tried changing the monitor to this old "Smile" CRT, with no change.

OS is WinXPpro. Has me stumped.
The BIOS and case are both locked.
The users only had "limited user" access.

Could the mobo be bailing?

 

[bupkus]

Since I have two computers with the same Asus "A7N266-VM AA" motherboard, I simply took the hdd from the problem one and installed it into the good one. Sure, it found a lot of new hardware (I thought they were the same mobo), but it ran in proper video mode. I'm thinking of installing a new hdd and installing a new OS and if it still is bad, I will know it's the onboard video.

Could someone have gone inside the case and changed any jumper setting? I really don't think so.
Could someone have gone into the BIOS? No, it was supervisor password locked.

I'll probably have to set it aside for a cheap video card.

If anyone has a better answer, I'll be here.
Thanks.

EDIT: I don't know what just happened, but the OS just asked if I wanted to let it update the video resolution and I said yes and it did. I think what happened was, when I put this hdd into the other pc, it righted itself through detection. Then when I put it back I neglected to check the video options. Yah, I know; I don't have a clue.