What's the purpose of using Firefox if you lose all your customizations? Just like Emacs, Firefox rules because it's customizable. On my Linux box, Firefox crashes tens of times a day. I've not dumped it yet because it's the only browser which allows me to customize pages' colors in a reliable way.
I’m not saying that your customisations are breaking Firefox, I’m saying that something in your profile has gone awry and is causing it to crash. I’ve not used the page colour customisation but it’d be worth trying a stock Firefox then dropping your customisations back in to see if that fixes it.
You can also see a list of crash reports from your install by going to about:crashes . These link through to the Mozilla crash log server, which often then links onto the appropriate bug in Bugzilla. You might find that what’s causing the crashes has been fixed in an upcoming release.
Is this a mozilla.org build? If so, what does about:crashes say? Can you paste some of the links here?
If this is a distribution-provided build, it might still have a working crash reporter or not, depending on the distribution. Check about:crashes, and if the links there don't do anything useful try reproducing the crashes in a mozilla.org build?
