Welcome to Justanswer.com, my name is Dustin.I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
You should be able to select the volume control / slider and add it back to your chromebook as follows
Now, the volume slide should appear in the panel at the bottom right of your computer..
If you get stuck or run into any issues, let me know.
I strive to provide great service, and greatly appreciate a 5 star rating clicked and submitted when you are satisfied.. I always answer follow up questions.Dustin S.Senior Technician and Network Switching Systems Operator / Maintainer.
Hello again,I havent heard back from you in a while. Did you still need help with this issue? If so, please send a reply when you can so we can continue working together.If everything worked out, please remember to click and submit a 5star rating to show that I was able to assist you.Thank you,Dustin S.Senior Technician and Network Switching Systems Operator / Maintainer.