Distorted display after Mavericks upgrade

Hi,

Let me start by saying I am not the most savvy person when it comes to technology!
I decided to upgrade my Mac Mini OSX from Mountain Lion to Mavericks last night. I thought it had been long enough that any problems may have been ironed out.
So I started the download and went to bed, this morning I have the prompt to restart the Mac, so I did. After it started up I got a heavily distorted screen and cannot do anything with the computer. I have tried to restart it a couple of times and it keeps doing the same thing. I have attached a photo for reference.

I would love some advice on what I can do, if anything, to fix this problem. What an awful screen to look at!!!

Thanks so much in advance!!

Hi,

Thanks for the reply - it ended up being a rather simple issue (a little embarrassed to say) but I unplugged the HDMI cable and restarted and it started fine.