No picture on Samtron 94v with geforce 5200

Hi I've just bought a Samtron 94v TFT from Staples and I'm having a problem with it. Every time I boot my PC I get a brief flash of Windows XP boot screen and then nothing, I have to switch the monitor off and then on again to get a picture but this only lasts seconds before the screen goes blank again. I've tried the monitor on another PC with a 5200 graphics card and it does exactly the same. It has worked but that was after continual switching on and off and if I tried to adjust it in any way then the picture disappered again.

I'm stumped as to wether it's the graphics card or monitor so can anyone shed some light on the matter.

Sempron 2200
512 mb ram
60Gb hard drive
Asus Geforce 5200 128mb AGP card
Lite on DVD Rom
NEC 3520 DVD-RW Drive
PC Chips 848 motherboard
ADSL PCI Modem
Firewire card