My Imac will not restart without me holding the power button
Ok so here is the issue my imac desktop computer is currently running Yosemite 10.10.3 and I am trying to do the upgrade to El Capitan to see if that fixes my problem but currently every time the computer says it needs an update it does it and then when it gets to the part where it needs to restart it shuts all the windows and icons on my desktop down and then never restarts. I have left it alone for hours and nothing just stays on my desktop wallpaper with no icons I end up having to hold down the power button to force it to shut down. It also does the same thing if i try to manually pull down the window and click restart or shut down it just shuts every thing down and leaves it on my desktop screen with nothing for me to click on.
iMac, OS X Yosemite (10.10.3)