Hi guys, I have an old cpu, HP Compaq dc7700 sff that is displaying in monochrome. I have tested several monitors, therefore I think the problem is with my cpu. I don't have a gpu card.
My monitor is not displaying in black and white, it looks greenish. I have even tried reinstalling different versions of Windows, but it can't get right. I also don't have a dedicated graphics card.
If your monitor works properly with another system, then I would think that the problem is with the video portion of your motherboard. Unusual problem.
I believe in cleaning as the first step to solving any problem... a bit of corrosion or a broken solder joint on a connector can interfere with transmission of color - for VGA connector pin 1 and pin 6 carry red signal - so inspect your connectors carefully under strong light and magnification.
Try with a different cable between the PC and monitor. If no improvement Cycloid is most likely correct in which case you may want to buy a new computer.