Certain website videos will not play on windows xp machine

My friend has a computer with windows XP SP3. She has most of the latest updates (not sure if there are still a few to be installed). And one website's videos will not load. She tried in internet explorer and firefox. They work fine on a Windows 7 machine.

When clicking to watch the video there is just a black screen, nothing else. I tried clicking on the video on the windows 7 machine to get info but no right click options are available. I tried searching through the page info to see if I could find a direct link to the video but I couldn't figure it out. It's a foreign website, unfortunately. Wanted to see if anyone has any ideas.

This is the website below (a direct link to one of the vidoes). You have to click on ASSISTIR to start playing the video. Thanks.

I've thought about that but in the past I've read people saying to never install K-lite as it can cause a lot of problems. Maybe things have changed more recently?
I've used klite codecs so I can listen to mp4 on my xpsp3 pc and they have not messed anything up, have been using these codec for 5 or 6 years.
Would you mind testing the video from the link I posted to see if it works on your XP machine with the k-lite codec?

I tested the video link with both using klite and without klite, clicking on assistir gives me a buffer circle and then a black screen with an x in the upper right that when I click on it turns it back to the original page.
So it looks like K-lite does not help. On windows 7 machines (I tried on 2 of them) it buffers for a second and then the video starts playing. I can't right click on the video to get any info so I don't know what kind of player it is or anything like that. Maybe this site simply does not work on windows xp (I tried with Internet Explorer and Firefox on the XP machine).

Thanks for testing it.
could be, I do not know enough to figure out how to get some websites to play videos, that is the only website I have been to that I could not have played the video.
I tried with k-meleon (firefox light) and it's not playing, which is weird... (just a black screen).
It seems that the site you linked uses a custom player made in java.
When I used the avast safe zone browser (a custom browser made using chromium sources), instead, it displayed "your browser doesn't support the playback of this video", which means that, probably, an updated version of chrome will.
Try with chrome and let me know.
Unfortunately, I had to uninstall it 'cause it requires too much ram for my poor, old system.
She doesn't have an extremely strong aystem either and I've heard chrome ises alot of respurces. She is not gonna want to install a new browser just for this one website givong her problems. So i dont think i will be able to test that. Maybe i can try to update her java. Will have to look at that.

Tha ks for trying it.
We expect all versions of Java that were supported prior to the Microsoft de-support announcement to continue to work on Windows XP for the foreseeable future. In particular, we expect that JDK 7 will continue to work on Windows XP. Security updates issued by Oracle will continue to be pushed out to Windows XP desktops. Users that download JDK 7 from java.oracle.com or java.com will continue to be able to install on Windows XP.

JDK 8 is not supported on Windows XP. Early versions of JDK 8 had known issues with the installer on Windows XP that prevented it from installing without manual intervention. This was resolved in JDK 8 Update 25.

above from HERE