T140 black screen

Hello, I've just recently purchased my first server ever. It's a power edge t140.

When I first powered it on I was able to boot into windows server as it was pre loaded.  I continued to add security and microsoft sql server.. However after leaving for a few minutes it is on black screen even after reboot. Im still on black screen. 

I've tried to log in as if the screen is just not updating and still nothing.   How can I get back into this server?