That's very strange.
Regarding when you say "after installing Presonus", are you referring specifically to the Studio One software?
Are you also using any PreSonus hardware? If so, what kind of hardware and which drivers did you install for it?
Regarding the issues with YouTube and other media, that won't have anything to do with Studio One. It's much more likely going to be related to whatever audio hardware interface you are using.
You can try this guide which may help the media playback issues outside of Studio One:
*NOTE: If you are not using an AudioBox, you can still follow this guide's steps for whatever device you are using.
I would recommend logging in to your my.presonus.com account, clicking on "Support", and creating a support ticket.