Video thumbnails not showing (NicoNicoDouga: Japanese site)

Hello, I don't know if I should post this problem on Firefox forum (because I use FF as my main browser) or adobe forum but I'd like to post it here first to get some suggestions.

Basically starting from few days ago, thumbnails won't show for some videos on Japanese video steaming site called Nico Nico Douga. Here are some of the examples on Firefox (highlighted in red rectangles):
https://i.imgur.com/DH7lbOp.jpg
https://i.imgur.com/CTwKEXT.jpg
Also, it won't show on IE as well as you can see from the screenshots below:
https://i.imgur.com/SuFDpmj.jpg
https://i.imgur.com/990wrGj.jpg

However, the problem is not permanent as when I refresh the page it shows the thumbnails. Though when I refresh the page again other videos will not show the thumbnails and so on. So, it's very random and it only happens to few random videos as there are no specific pattern for certain videos.

I know it might be hard to pinpoint the cause of this problem as it's not a well known site like youtube however I suspect the way it works (i.e video thumbnails, using same flash player etc) is similar to each other.

I've tried:
- Safe mode: the problem was still there
- Uninstalling Flash player plugin completely: even without flash player itself, the page still shows some videos with missing thumbnails
- Downgrading to previous version of flash player: still there
- Tried on other browsers: same result and here is screenshot of Chrome https://i.imgur.com/wnbwU8y.jpg
- Upgrading my FF to latest version (22): same as above

Hmm, this is strange...

Oh and that site doesn't run on Java. It's pretty much same as youtube without html5 video playback support.

A Guy said:

Here is a longshot

Thumbnail Cache - Clear and Reset

You seem to have a system problem, rather than a browser issue. Do you have a System Restore Point from before the problem began? That may be easiest.

Try the site through Safe Mode with Networking

Safe Mode

If it displays thumbs correctly there, try a clean start to see if there is a conflict

Troubleshoot Application Conflicts by Performing a Clean Startup

A Guy

Clearing cache didn't solve the problem and even when start in safe mode, the problem is still there.

I don't have a restore point (before this issue started to happen) unfortunately.

Britton30 said:

Here's a longer shot...

This may help, run the steps outlined in this tutorial, Option Two, and reboot the system:
SFC /SCANNOW Command - System File Checker
If that doesn't correct the issue, run it two or more times with a reboot between.
You may get this result:

Code:

Windows Resource Protection found corrupt files and successfully repaired
them. Details are included in the CBS.Log windir\Logs\CBS\CBS.log. For
example C:\Windows\Logs\CBS\CBS.log
The system file repair changes will take effect after the next reboot.

Or a message that no integrity violations were found.
Or that Windows Resource Protection found errors it cannot repair, if so rerun the steps above.

Do you have the same problem with other browsers?

I've tried five times and it didn't fixed the problem (All messages were: a message that no integrity violations were found.)

And yes, I've tried different browsers (IE and Chrome) and it still showed the same symptom.

A Guy said:

Try it through a web based proxy. Untick all the boxes below the form

Start Using CGIProxy

A Guy

It still didn't work...