Camera does not work on zoom but works everywhere else

My camera suddenly stopped working during a zoom meeting  2 weeks ago.  I have uninstalled and installed the most updated zoom version.  Turned my computer off and restarted it.  Nothing seems to work.  I have brought my laptop into a shop 3 different times to be fixed, and it is still not working.  Would really like to get some guidance on what's going on with it and how to fix it.