From doing a little research I can suggest doing a few things. Restarting Windows file explorer is my first suggestion. A lot of problems with the taskbar is caused by windows explorer. This can be done with the following steps:
- Open file explorer
- Hit Control+Alt+Delete and select Task Manager
- Navigate through the Processes tab of task manager until you find a process called Windows Explorer
- Right click on it and click Restart
- Wait a few moments and try Youtube, Netflix, or opening a photo after your taskbar reappears
My second recommendation is to restart your computer use Windows in “safe mode”. This mode boots Windows with only programs necessary for operation. A guide from Microsoft on how to do this can be found here. After booting into safe mode, then you can try to open a photo or watch Youtube/Netflix. Hopefully the first one works. If the second one helps let me know so that problem can be troubleshooted further.