https://www.anvsoft.com/any-video-converter-free.html
The above is totally free and works with a number of online video sites. Says it works with XP.
You can use it to download videos, and you can also convert videos to other formats. Even though it looks like it is meant to covert every single time, you don't have to...it saves all the downloads to a folder on your PC...you do not have to convert them. I've used this software from time to time, so it has my seal of approval...lol
Although I haven't used it in a while, I recall when installing it there was no bloatware or anything that tries to trick you into installing some intrusive browser search bar or anything semi-malware like that...as you might get with some other "free" software.