If your computer is not booting with the two RAM sticks, the problem might be with your RAM sticks or the RAM slots. In this case, you can do one thing. Insert only one RAM stick at a time and start ...
Take it back out and see how it goes? If it works, go into the BIOS and make sure it is set to allow 'auto' or 'detect' graphics output method. It might still use the onboard output. You could try ...