The only tool which shows up on my screen is a pencil with a circle next to it. The circle has a line through it. I am unable to use any tools.
Have you axctually created a new document/ artboard? What system are you on? You need to be more specific.
This usually happens if one is trying to draw on a locked layer.
Check your Layers palette.
Sorry to hear about this experience. As suggested by Kurt, this could be if you have a locked layer selected. I would recommend checking if the problem persists with other documents, as indicated by Mylenium. If yes, kindly try resetting Illustrator's preferences by following the steps shared in this article (https://helpx.adobe.com/illustrator/kb/troubleshoot-preference-issues.html) and sharing your observations.
Disclaimer: Please note that resetting preferences will remove all custom settings, and Illustrator will launch with the defaults. You may take a backup of these settings from the location mentioned in the article.
Looking forward to hearing from you.