Help with external iMac screen solution

OK so I dropped my mid 2011 iMac 27 on its head. I now have a black screen.

The iMac powers up (I can hear the chime and also the dull noise when entering the password wrong). I have had a quick look and all cables are attached inside.

I tried to connect with a thunderbolt to VGA cable on a external monitor. I could only see a very blurred version of my Yosemite background. I could make out the blue and orange but it was just a blur. Couldn't see any icons etc as just too blurry.

ANY ideas how I can get my data off? I have a 2017 4K iMac with the new thunderbolt cable. Which is the best solution to try and get some view of the old screen so I can drag the files onto a external drive? Also any idea whats up with the thing!

Thanks in advance

Mike