Help! Damsel in distress :(

Which is at fault, monitor or graphics card?
I have been having problems with the monitor and grahpics drivers. The monitor cuts out and stops responding at certain times and sometimes when you boot up the computer the monitor does not come on it just flashes like it is on standyby mode. I have downloaded the lastest drivers from ATI and windows update and this seemed to fix the problem, but now it has started to happen again. The graphics card up to this point has worked fine (Connect 9800 Pro). Could it be the new monitor? (Samsung SM793S 17ins Fst 0.23 96khz TCO03)

Could you please help me with this?

Mobo:Intel D865GBFL SKT 478 ATX AGP8x FSB 800 LAN
Ram:2*256 Corsair XMS 3200
HDD:WD Caviar 800JB
OS:XP Pro

It definately sounds like it's the monitor's fault. The graphics card drivers are only loaded when Windows boots up, so in the time between when you turn your PC on and Windows starts loading, you should see at least part of the normal POST screen.
Obviously, the first thing to check would be that the monitor cable is firmly plugged into the graphics card. Apart from that, a new screen shouldn't be behaving as it is. As an alternative, you can always try plugging the monitor into another PC (Assuming that you have one), and see if behaves in the same way. Otherwise, you should take it back to where you bought it, letting them know of your problem, though this'd be a tad difficult if you bought it online.

I'd point to the monitor - the internals may not on its last legs. Have you been able to test it with another system/gfx card?

Other than that have you changed/added any other hardware in the PC recently? A failed POST could be display related or potentially a struggling PSU. Which brings the question whats the PSU?