Dave-H

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.

I've just noticed today that videos don't now seem to be appearing on Instagram pages with Firefox ESR 52.9.0. There isn't even a placeholder, they are completely missing, all that's there of the posts is the text that should be beneath the video frame! Static images are still displaying fine. Is anyone else seeing this? They were fine yesterday! The videos are still fine in Firefox 65 on Windows 10 needless to say. I've tried spoofing the browser user agent using an extension, which I already have to do to get Facebook HTML5 videos to work, but none of the ones I've tried make any difference on Instagram.

Yes, me too. Still no replacement for MSO.DLL, KB4462174 still hidden. I assume Office 2010 is supported until next year, as it's usually ten years of support. I wonder if we'll ever see a fix for this?

Rather late in the day to this, and I'm sure this has probably already been tried, but if I had this issue I would try uninstalling everything in Device Manager, ignoring the reboot notices of course, and then see if the machine will boot in Safe Mode. If it does, then it must be a driver problem and then it's just (ha-ha!) a matter or narrowing down which one it is. When you reboot normally the OS should put all the devices back again as you haven't actually removed the driver software from the machine (there's an option to do that on uninstall on later versions of Windows, but not on XP). It may actually put them back differently, which might also affect the problem.

Thanks @jaclaz. It may not be difficult for you, but it is for me! I'll leave things be for now, but I would be very interested if @rloewcan write a program that will correct the issue without reformatting. If he does I will certainly buy it and use it.

This is all way over my head I'm afraid! My NTFS drives were formatted by Windows 10, so presumably there's no problem there. My FAT32 drives were all formatted by Windows 98SE. Is there therefore a problem I need to address with the FAT32 drives, and if there is would any solution mean I would have to reformat them? That I'm not keen on doing of course, but if it's going to mitigate against problems in the future, I'm willing to consider it. I do need to format quite large drives with FAT32, but I'm pretty sure that Partition Wizard can do this, presumably with correct alignment. I said "Partition Magic" earlier, when I actually meant "Partition Wizard". Sorry if that's caused any confusion!

The free version of Partition Wizard, which I've used for many years, has an "align" function, which I'm pretty sure I have used in the past on my FAT32 drives, both SSDs and conventional drives. Will that actually fix this issue where I've partitioned and formatted drives using Windows 98 Fdisk? The reason I used that method was because the size of FAT32 partition you can create with Windows XP and later is quite limited.

So is that a problem I should worry about? It's been like it for several years now and there doesn't seem to be any symptoms of things not being right.