video playback problems

I’m not a particularly computer knowledgeable user. Two days ago I downloaded Audacity on my six month old Dell that is running Windows 10. I allowed the Audacity download to change settings as needed. Since that time, I’ve been unable to run videos feeds from MSN, Youtube, etc. Can anyone tell me how to fix this problem?

Thank you for responding so quickly. I have Window 10 Home version 1607. I downloaded Audacity from your site two days ago and clicked on the standard Windows download, version 2.1.2. I’m pretty sure I used the .exe installer…I do not remember a zip file.

Audacity does not change settings on your computer.
If you are using a USB audio device, see: http://manual.audacityteam.org/man/faq_playback.html#usb