iMac failing software updates and el capitan

Hi. My iMac keeps failing to update El Capitan. It will start off extremely slow and then eventually fail. Even the most recent iMovie update fails to download. The iMovie file is only 333mb but it will still stall out.

While typing this, I opened the app store to try and update again, and this time it wont even load either. It says its not connected to the internet but i have full wifi connected.

It is a mid 2011 27" imac running Yosemite.

Can anyone point me in the right direction?

Reboot and try again would be my advice. I have an early 2009 MacBook running El Capitan and yet, I'm not having any problems updating apps - at least not to this point in time.

Thanks. I had already tried that a few dozen times. No luck