I Mac will not programs after installing updates

[Rudy Varney]

Basic info: I have a desk top I-Mac 21.5 inch, purchased new in 2012
Computer worked fine in the morning. Left it on during the rest of the day and returned that evening to turn it off. During my absence the latest software updated was in stalled. The next morning I turned on the computer and every thing went normally until it got to the status bar located underneath the Apple insignia. It usually takes 30-35 seconds to load the software and display the home page; however, it now takes 15-20 minutes before even the status bar is displayed on the screen and another 30 minutes before the status bar completes its process. Then, that ‘s it, no screens ever open up. I have tried again and again and get the same results.
Any thoughts! I‘m not computer savvy but love that darn thing.
Rudy

 

[mgmcc]

Do you have a "Time Machine" backup that you can restore the iMac to its previous version from? If not, are you able to start up in "safe mode" (hold down the shift key when powering on and until the apple logo appears)?