Only one thing comes immediately to mind: occasionally I've seen the image not refresh, particularly if I go "Back". You can use Ctrl+Shift+r to reload the page bypassing any cached CAPTCHA image.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Note that your System Details List shows multiple Flash plugins.

1. Shockwave Flash 12.0 r0
2. Shockwave Flash 11.8 r800

You can find the installation path of all plugins on the about:plugins page.

You can check the Flash player installation folder for multiple Flash player plugins and remove all (older) version(s) of the plugin (NPSWF32) and (re)install the latest Flash player.

• (32 bit Windows) C:\Windows\System32\Macromed\Flash\
• (64 bit Windows) C:\Windows\SysWOW64\Macromed\Flash\

I think the problem was the multiple versions of Flash files in the directory. I just simply moved the old version files out of the installation directory. Restarted the browser, then went to look at the flash extension. There was only 1 version, but it was not active. I changed to Always Activate and restarted my browser.

At this point I checked to see if captcha was working, and it was.

Thanks for the help. I just don't get why Adobe doesn't remove the previous versions.

I have the same problem, and do not have multiple plugin versions. However, also when I click on the "listen to the numbers" option under the image on the eBay page, the audio player does not appear, like it does in IE - so you can't even listen to the numbers. It is only eBay that I have these problems; captcha and audio players work fine on all other sites. What could make it only fail on one site - and one of the most popular/visited there is?