Hello Diane,
Upon installation of TotalAV it should have disabled windows defender, you might want to make sure windows is up to date, along with un / reinstalling Total AV. You should never run two different Antivirus software at the same time.
After installing Total AV again you might see a dialogue prompt from windows Defender wanting to turn itself back on, at this point you should choose the ignore option.
I hope that helps, let us know how it goes.