Well with the nVidia driver installed, my monitor would often go black and get a "No Signal" error. When this happens, I can't really do anything other than restart.
After I went into Safe Mode and uninstalled the driver (currently running on my system's generic video driver since I have nothing else), my computer stopped encountering these problems (although now its rather laggy and the graphics aren't exactly the best anymore) so I'm pretty sure the nVidia driver is the thing that's causing me problems.
Not sure if this is the information you wanted but I got it from running the DxDiagnostic:
System Manufacturer: IBM
System Model: 8187D1U
BIOS: Phoenix FirstBios(tm) Desktop Pro Version 2.0 for IBM ThinkCentre.
Processor: Intel(R) Pentium(R) 4 CPU 2.66GHz
Memory: 1278MB RAM
I was going through the Dell website and it led me to find the "ATI Radeon HD 4350 PCIE 512MB DDR2 Video Card".
Would this graphics card be a good buy? I was considering it since it is only $50 and my computer seems to fulfill all the minimum system requirements, I think.