Monitor Problem (Flatron 795FT Plus)

I have a Flatron 795FT Plus (it's a 17" flat screen (screen not panel) with
a 4 port USB hub on the back of it.)

Ok the problem: A while back it started turning off and then coming back on
again. Thereis no pattern that I can discern from when it happens. I
finally got annoyed enough that I stuck an old monitor on this computer
instead and I have been using it (It's horrible, color is bad, hurts my
eyes, etc). So I'd like to get my old monitor working again since it's a
wonderful display.

Recently I upgraded 85% of the hardware in this computer (fuzzy logic
insert: at what point does the computer stop being the same computer it was
before and become a new computer). That upgrade included a new power
supply, so I decided to give the monitor a shot. Since getting behind this
computer is a pain I hooked it up to one of my other computers first, and
ran it for 4 hours continously. It ran fine, didn't so much as flicker.

Well, as you've probably guessed where this is going, I plugged it into this
computer and.. nothing. It has power because it would give me the amber on
the power button (the "I have no signal, but I do have power"). About 45
seconds later it gave a picture, if only for 20 seconds or so.

Anyone have any ideas?

The other computer I had it working on is a significantly less powerful
machine (p3 550 vs. amd xp 3200), power supply on the working one was most
likely a 250 - 300. This one is a 450. Graphics card on the working one is
a GeForce2, this one is a radeon 9700pro.

I'm trying to use another cable to connect them (it's one of those monitors
that has the removable video cables), to see if maybe there is a problem
with the cable), but I don't think that is it.

Both computers are running same OS (winxp pro), both using default plug and
play driver's for the monitor.

Would video drivers cause an issue? Monitor drivers and video drivers are
different, but do they sometimes conflict?

At this point I believe it to be a hardware problem with the monitor, and I
would love any suggestions agreeing or disagreeing with that.

Thanks for reading the whole thing, I know it was long.

~Chris