I think I have a virus in my Mac Air but do not know how to get rid of it and it is getting worse.; My browsers, Safari and Chrome, crash constantly or they freeze. My mail and other apps do the same thing. The wheel of dread spins and I can’t use a

Try setting up another admin user account to see if the same problem continues. Please post back on whether or not this worked. Also try the Safe Mode. Please post back on whether or not this worked.

Isolating an issue by using another user account

Safe Mode - About

Safe Mode Startup – El Capitan. also Sierra

If it works in the Safe Mode, try running this program when booted normally and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor. Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown.

Etrecheck – System Information

Macs can get viruses. This has been documented. However, crashing apps is not necessarily a symptom of a virus. Follow the steps in this article (It says macOS Sierra but applies to the other OS versions as well) and if that doesn't work call Apple: macOS Sierra: If an app freezes or quits unexpectedly.

In the US AppleCare 800-275-2273 between 8am- 11 pm EST

Install Free Antivirus Replacement & Anti-Malware Tool | Malwarebytes

virus rarely install in Mac even if you create a new user test account , the malware or adware will remain the Mac that will not be removed , you have to scan the Mac using malware bytes to get rid it .