Resolution stuck at 4-bit

[Superglup5]

I have a Dell Dimension 2350 with Windows XP that I took off my grandma's hands. The picture was fine (not sure what it was exactly), but I formatted the hard drive because of her tendency to download viruses. Now the quality is stuck on 16 bit, there are no other options from the menu, and the lowest resolution. Next I tried updating the service packs but that just stuck it at 4 bit. I looked around and now think the APG apiture size needs to be adjusted but everything that looks like would work in the BIOS is gray-ed out and and can't be adjusted. I'm using the same monitor as when the computer worked and don't know what to do.
Thanks in advance.

 

[shortstuff_mt]

Sounds like you need to install the drivers for the GPU.