Dave-H

You'll feel at home where I live, in Ealing in West London, there's a huge Polish community here!

It's not even available in different versions of English. US English only.

I assume you've tried a clean startup using the system configuration editor? Is the problem still there if you do a clean startup?

I got a free "upgrade" from Windows 8.1 after the original offer ended before I decided to bite the bullet, by saying I needed Windows 10 for its accessibility features. That was a limited time offer supposedly though, so whether you can still do that I don't know. There was certainly no check on whether you genuinely needed it for that reason or not!

I wonder if MS will restart the free (and perhaps automatic) "upgrade" to Windows 10 "offer" for Windows 7 users when it approaches EOS? If that extends to Windows 8.1 as well, I'll have to be on my guard again on my netbook, as any update to Windows 10 will hose it as there are no compatible graphics drivers for it!

@VistaLover I tried that UA string too, and I got past the first incompatibility error message, but then got a WebGL error message instead. Switching over to my other graphics card, which is much better than the ancient one I normally use on XP, made that error apparently go away, but I've now just got a static picture which appears to have no embedded links, so I'm not sure what you're supposed to do with it to try and go any further.

Thanks, that's very interesting and good to know, but I think I'll stick with the extension, I can see more quickly and easily how that's set, and it doesn't seem to be causing any performance problems.

How do you do that on Firefox without an extension?

I use an add-on called "Custom UserAgent String" which should do that for you, and it will "stick". I have it to spoof the user agent just on Facebook so it serves HTML5 video as it was otherwise dropping back to Flash. There are other add-ons which will also do the same thing, essentially restoring the functionality that Presto Opera had to change the user agent string on a site by site basis.

@xrayer Have you tried reducing the resolution and/or colour depth on the Nvidia Control Panel? Obviously it's a severe problem, but if the Windows Explorer being unstable is the only issue, and all other display functions are fine, I wouldn't have thought that the driver itself was unstable or the card physically faulty. I would have suspected the shell extensions as being the likely culprit too, but if you have disabled them and it makes no difference presumably it can't be that! FWIW I have Nvidia driver version 320.92 installed (this is a Quadro driver, not GeForce) and it works fine, and before that I had GeForce 340.52 installed with a GeForce card, and that worked fine too. Maybe try that version as it certainly worked for me.

I don't know about the others, but to get Otter to work with HTML5 videos on YouTube, I had to replace some files with those from the XP SP2 compatible version. See here. You can download otter-browser-xp2.zip from here. Extract it to a temporary location, select all the files in the Program Files\Otter\lib\gstreamer-1.0 folder, and paste them into the same folder of your working version of Otter, overwriting if necessary. I found that made YouTube videos work fine in Otter on XP. I did it ages ago, and have never had to repeat the operation, even though Otter has been updated many times since then. HTH.

@mixit You sir, are a genius! The addition of the css file (my chrome folder was empty) has fixed it perfectly! I love this forum so much!

Thanks @Mathwiz, I'll have a look at that version of Serpent and see how it goes. I'm not thinking I will abandon FF52ESR imminently. The Instagram video issue is annoying, but I can obviously still view them on my phone or on other browsers (including Google Chrome 49 on XP!) so it's not the end of the world. If other sites start breaking though, I will have to reconsider. Cheers, Dave.

Off topic here of course, but while we're talking about browsers to possibly replace FF 52 ESR, do any or all of these browsers sync with versions of Firefox using the Mozilla sync system? I have other Firefox installations, all of which are the latest version on my phone and on Windows 8.1 and Windows 10 computers, and I wouldn't want to lose bookmarks, history and password sync with them if I went to another browser on Windows XP. EDIT: Thanks for moving this to a more appropriate thread, whoever did it! (@dencorso?)

I can vouch for that, and believe me I've tried! It worked to get Facebook videos back to HTML5 after they dropped back to Flash a while ago, but that's not the same problem as now with Instagram. The fact that the videos still appear in the Page Info dialogue, and will play there, but won't appear in the pages where they should be, would seem likely to be caused by a scripting change Instagram made a few days ago for some reason, which Firefox 52 ESR either can't cope with or doesn't understand at all. The fact that placeholders don't even appear where the videos should be would bear that out. I've seen several posts where there is both a video and a still which can be sideways scrolled between. In that case the still appears correctly, but the video just appears as a white box. In my experience this is the first major compatibility problem to surface after FF 52 ESR came out of support, and I don't think it will easily be fixed I'm afraid.

Thanks @jumper. If you look in the plugins folder in the zipped version of my Eudora 7.1, you will find all the plugins I have installed in my copy of Eudora, which is basically all the plugins I could find online! Cheers, Dave.

@jumper Did you manage to get my upload of Eudora 7.1 to run?

Isn't the MIME type just "video/mp4"?

Yes indeed, see here.

Thanks, that's very interesting as I was having some problems accessing Instagram earlier on today intermittently, and that's probably why. It doesn't explain the problems with the videos displaying though, as they have carried on working in other browsers, just not on Firefox!

Absolutely, Classic Shell (now Open-Shell) is one of the greatest programs ever released IMO, and it's free! It was the only thing that made Windows 8/8.1 usable for me, and even improves the Windows 10 UI enormously. Its writer cannot have enough praise from me!

Yes, my normal installation of Google Chrome 49 (the last that works on XP of course) displays the Instagram videos fine, as it always did! Even more strangely, if I look at the Instagram "Page Info" on the right click in Firefox 52, on the media tab the videos are still listed there, and if I click on them they appear in the preview pane below, and can even be played there. They just no longer appear on the actual Instagram pages! This is very strange indeed, as they obviously aren't actually blocked, they are just not displaying any more on the pages as they should do.

Just tried changing the user agent, but absolutely no difference I'm afraid. Facebook videos still seem fine with - Mozilla/5.0 (Windows NT 6.1; WOW64; rv:57.0) Gecko/20100101 Firefox/57.0 Should I change that to the later one? Addition: I've just tried with Google Chrome 49, and Otter, and the Instagram videos still work fine there! Very strange, as Google Chrome 49 is far more out of date than Firefox 52ESR!

All fine here (touch wood!)

Thanks everyone, so Instagram presumably changed something yesterday to cause this? The videos were working fine for me up until then. They never played automatically like they do on my phone, I always had to manually start them by clicking on the white play icon in the centre of them, but it's like that on Firefox 65 on Windows 10 as well, so I guess that's a "feature" of the desktop browser version of Instagram. Very annoying, I wonder if there is a workaround for this like there is with Facebook, where the HTML videos do work if you have the Primetime plugin installed.