Can I have an old version and the latest version on the same machine
lumosity does not work with the latest version of firefox (it loses key presses for the arrow keys). So can I keep an older version of firefox on my computer to be used only with lumosity and the latest version on my computer for all other browsing activities. Lumosity says this happens on firefox versions 25 and above. If I can keep two versions resident on my computer, what version prior to 25 would you recommend for windows 8?
Alla svar (3)
It's tricky to run two different versions of Firefox at the same time.
If you don't need to use other websites while you're on Lumosity, then you could use the "Portable" version of Firefox 24 for Lumosity when you want to use that site. (See: Portable 24.0) Since that does not have the security fixes from Firefox 25, 26, 27, and 28 you really should not use it for other sites.
On the other hand, maybe it's easier to use a different browser for Lumosity (such as IE or Chrome) until they resolve this issue?
You can install the Firefox 24.4.0 ESR version via a custom install as that version is supported with security updates.
Make sure not to start that version, but use the Profile Manager to create a new profile for that ESR version.
By the way, Lumosity says this is an intermittent problem that you may be able to clear by refreshing a couple of times: Arrow keys are unresponsive in Firefox : Help Center.