Hi Dasp1976,
I.ve bought some time ago a dell precision m4800 for the future CAD/CAM works.

Running the Cnc, I don have anything special at the moment:
Intel Pentium dual cpu e2180 2.00ghz 2.00ghz
2gb RAM, 32bit operating system
video card intel 829456 express chipset family
128gb SSD, windows 7 home premium with windows 7 basic theme
paralel port built in

in device manager, in Computer, i have only 2 drivers available: ACPIx86 based pc, and Advanced Config and Power Interface (ACPI) PC. I don.t have Standard PC option. Some people say that this can be a fix for steppers missing steps, or making strange noises.
here is a link to someone who is talking about this issue. skip at min 4.30 https://www.youtube.com/watch?v=n18OTfjbFp4

also in device manager, in Mach3 Pulseing Engine, I have Mach3 Driver version 6.1.0.0 (4/20/2011)

I.m mentioning all this because, running DriverTest in Mach3 installation folder, I get all 3, Pulsing to slow/Pulsing to fast/System excellent messages. If I move or drag any window on the desktop, while the DriverTest is running, I get lots of spikes in that otherwise straight line. Some people say that changing the driver mentioned above to Standard PC will fix this issue, but I could not find what to do if this driver is not available in the option list.

But I guess, as this pc units are very cheap, it does not worth spending so much time troubleshooting the one I have.
I.ve read dell 760.s work fine, but this are core2duo.
You mention single core machines, intel celeron and windows xp. Seems a safer and more stable choise. I.ve found a couple online, to my surprise.
I.ll get back when I have one.

Thank you for your reply.