No display and keyboard, need to connect to external monitor

Here's my problem, I have a laptop but its display and keyboard are not working. I have an extra monitor and I want to connect my laptop to that monitor. The fn thing does not work because the keyboard isn't working. The drivers are all installed properly. It even worked once but then it stopped working. The laptop is fine, I'm able to turn it on and off using and external keyboard. So is the monitor as I can connect another laptop to it. Please help!