How to test? Failed graphics...

I have a simple rig:
Dual Core
P5K board
ASUS 1GB Graphics card in PCI ex x16 slot.

There are no on-board graphics.
There is no picture coming through the independent graphics card.
When you plug the monitor into the card, it leaves the 'test' screen and goes into 'power saving' mode - some signal must be coming through the card surely for this to happen?

I have no other way of plugging the monitor into the computer.How do I test if the board is broken or the card?

Many thanks for any help!

Was the card working before? What is the exact model number of card you have? Does it require a 6pin pci express power cable?

The monitor isn't getting a signal from the GPU so it's power down.
Make sure that the GPU is seated properly, and power connections are seated as well if the card requires it
If you still have problems try a different card if poss

Do you see the post process, or does the screen just stay black when you turn the computer on and the monitor is already attached + turned on?

try resetting the bios / re insert the card / ram etc etc

If the card is bad, the system should still boot without any GPU installed. Confirm you have a PC-Speaker/Buzzer installed (that one may have one built in) and try to run the system without the GPU installed. If that's the only problem, you'll get the no video beep (what was that, one long, four short beeps). Typically from there, the system will complete POST, start booting (HDD activity) and get to the OS(Windows chime)

Next step if you can't tell it's booting, remove the RAM (still leaving the GPU out). Again, assuming the PC-Speaker is connected, you should get a no-ram beep (beeeeep...beeeeep...etc). If you still don't get anything, it's probably a bad board or PSU. If you do hear the beeps, try the sticks individually and see if it'll POST.