At least upgrade to SP3 as your current system is a disaster waiting to happen.
YouTube has changed significantly over the last couple of years so you will need to upgrade the browser. (The latest Firefox (Or other browsers) will have all the add-ons you need, plus they will be up to date) The fact that people refuse to upgrade for the latest security patches is why Microsoft had to force updates on later OS (You can postpone them for a few weeks) to bring them up to the standard of MAC and Linux OS which do it automatically. (And you don’t hear MAC or Linux users complaining)
You could also be infected, as security updates have stopped for SP3, so SP2 is an open book.
If you don’t want to pay to upgrade windows (Win 10 is the best windows ever in spite of some concerns) try Linux Mint (You can run it alongside XP) and add Wine if you have specific Windows programs you need to use. (You will still need an anti-virus/malware program as wine opens up Linux to the same problems as Windows. (Unlike the latest Windows Linux has no defences built in unless you use pure Linux programs and forget wine)
Most windows programs have an equivalent version in Linux but in a lot of cases will not have all the latest features as it takes time to port them over.
One more thing, most programs don’t even support XP any more so you should really change it ASAP.

Bill