Hey Assuming you connected the display cable to your graphics, getting image is at least a good sign.
Check this and give it a try. The error code should tell you what's wrong too. Example: Normally bad ram timings will have several boot loops and straight to BIOS with the DRAM light on. Example: Normally bad graphics card or something related to it, should light the VGA light. Example: CPU not present, faulty or even the BIOS not ready for it, again CPU light on. Example: No drives installed, boot drive faulty or absent, and something related to boot, yes indeed, Boot light.
But preferably, give us more info because my post is pretty much generic at this time