How can I remove virus from my macpro?

Try scan with malwarebytes.

You probably have some malware, no viruses.

Free Antivirus Replacement & Anti-Malware Tool | Malwarebytes

This program was written by long-term member of community here.

It’s easy to use and will find malware And can delete.

There is a reasonable chance the anti-virus you installed is part of your slowdown issues.

Run MalwareBytes as was already requested.

MalwareBytes Anti-Malware (formally AdwareMedic)

https://www.malwarebytes.org

And when you are finished checking (and cleaning) uninstall MalwareBytes

https://support.malwarebytes.com/docs/DOC-1928

Then please post the EtreCheckoutput as a "Reply" to this thread

https://discussions.apple.com/docs/DOC-6174 or https://etrecheck.com

Click on the Share icon and select "Copy Report"

.

And then Paste

the report as a "Reply" to this thread.

If, AND ONLY IF, you get the error:

"The message contains invalid characters"

then try posting to PasteBin.com, and give us a PasteBin URL link.

http://pastebin.com

.

EtreCheck is a tool that helps Apple Support Community volunteers debug problems without any access to the troubled computers. Debugging problems can be a difficult task even when the machine is in front of you. Attempting it via a discussion forum is extremely difficult. EtreCheck is a great help that regards.

I would uninstall Avast. It tends to interfere with the computer's operation while providing minimal to no benefit unless you work with Windows files. Most long time posters recommend not using antivirus software or cleaning software such as CleanMyMac.

Avast

Avast Un-install

What makes you think you have malware (note that there are very few "viruses" on any platform)? Did you install any of these downloads?