It will be sad to upgrade just for stability. Any other things are unstable ? Could you run these tests ?
1. Youtube only crashes in high resolution ? Or only when full screened ? Could you check ?
2. Install free non-activated windows to a spare hard disk or maybe pendrive (if supported) from here :
https://www.microsoft.com/en-in/software-download/windows10. See if that is also giving the problem. If so, windows installation might have an issue - I don't know how to fix but a reinstall should most likely fix it.
3. Or boot from a live image of any linux (e.g. ubuntu
https://ubuntu.com/download/desktop) without installing. Youtube crashes here too ?
4. Memory test : download free, create pen drive and boot from it :
https://www.memtest86.com/download.htm. Start test and let it run overnight, it will accumulate any memory errors.
5. If it is a specific kind of crash, like PAGE_FAULT_IN_NONPAGED_AREA : you could google for it and some solutions work like magic. For this, some solutions also ask to check disk drive using tools within windows, at least chkdsk. If that gives an error, a 10k SSD upgrade should solve your problems.