The first thing I did was swap the monitor for another one, then replaced the VGA and power cables. This didn't work, I then bought a replacement graphics card and fit that and the problem still persists.
I have also changed the screen time out options in Windows and in the BIOS.
The PC is a HP Compac dx2450 running Windows XP SP3. The replacement graphics card is a Palit 8400GS Super 512MB DDR3 VGA DVI HDMI PCI-E Graphics Card.
Any help would be greatly appreciated as I'm completely out of ideas now.
Edited by hamluis, 17 February 2012 - 07:28 AM.
Moved from XP to Internal Hardware.