Hi, SL.

Is that still Mint 13 on the old laptop you upgraded a year or two back?

If so, then support for Mint 13 ended in April, and it might be a good idea to move on to something that still gets security and other updates.

IIRC, you had an old laptop which couldn't run "non-PAE" software. If that's the case, then I don't think you'll be able to upgrade to a current version of Mint. LMDE might be worth a look; looks a little too clever for my taste! - you'll find more on the Mint site:

https://linuxmint.com/download_lmde.php

Firefox has made a few fairly major changes recently, and you might have fallen foul of these with your outdated machine. I don't know what CD is trying to get you to do, but I'm sure it could be useful.

Trouble is, you'll still be on an ancient version of Firefox. The current Firefox (from the Mint repositories, rather than the beta versions) is 55.0.2. (You might like to back your Firefox profile up before upgrading Mint/Firefox/ your computer - no going back from version 55, apparently. Not something I'e ever worried about, and I can't remember how to do it - a simple matter to look it up on the internet.)

If you're still running Mint 13 and your processor is one of the dreaded old non-PAE monsters, the simplest thing would be to treat yourself to a more modern machine and run a current version of Mint (or whatever you prefer).

I find the old Thinkpad T61 runs beautifully with Mint 18, and recently picked on up for about forty quid. Some sellers ask a lot more, and anyway, you might prefer something newer. Just a bit of personal experience - you don't need a shiny new machine to run a current edition of Mint which'll give you another three years or so, and might even be capable of upgrading to the next version.

In the short term, it might be feasible to back all your data up somewhere safe, then wipe the hard drive and install something compatible but more modern. I've recently messed about with antiX (the "legacy" version for old kit), and liked it very much. It used to be quite "manual," but looks easier now - and I think it supports non-PAE processors.

Post back if you want to discuss further!