Okay, I don't know why but I always seem to have trouble getting Untangle installed. I picked up a refurbished HP/Compaq DC5750 desktop with an Athlon X2 CPU and 1GB Ram, and an 80 GB HD.
When the system boots it stalled at first, I remembered from another system to select High Res mode and that seemed to work, but once the splash screen seemed to indicate bootup was complete and I am expecting the setup screens it is just black instead.
Pressing the power button I see the splash screen right away while the system is shutting down.
I haver done some searching, but I have not yet found a solution.