Which versions exactly?
Which other software is running in the foreground?
We're so sorry to hear that you're having trouble. Could you please share the details asked by Monika.
You may also try resetting preferences by following these steps and let us know how it goes:
Please note that resetting preferences will remove all the custom settings and Illustrator will launch with default settings. This way all your old settings will be saved in .old folders and Illustrator will recreate new folders with default settings.