Pc desktop monitor turned green can u help?

Is your computer a store bought (i.e. HP, ACER, etc.)? If so, tell us the brand/model. If you don't know, and also don't know where the MB is or the graphics card (if there is one), your best bet is to take it to a reliable repair shop.

Sounds like you just need a new cable, try a different cable first.

Are you sure the pins inside the connector aren't broken or snapped, sounds like something isn't connected properly and you'd have to hit it pretty hard to break a graphics card or motherboard