I got a cert, everything worked fine (Thanks so much!!), but I recently received a renewal reminder and I'm completely baffled. I can't find any of my notes from the original installation so I don't know what to do to get a renewal.
Also I had no account on letsencrypt (not sure why) so I created one just now.
Can you point me to some doc? I just don't know the next step.
If you obtained a certificate manually and sent it to your web host, then you will have to repeat that process again.
Let's Encrypt certificates have a 90 day lifetime, then they need to be replaced. This process is also called renewal, which you've received a reminder about.
In shared web hosting environments like yours, usually (and ideally) the platform would support automatically obtaining, installing and renewing certificates. Hosting platforms like cPanel and Plesk support this out of the box.
It looks like Arvixe doesn't support this type of arrangement, and your choices are to either send them a new Let's Encrypt certificate every 90 days, or pay them $25/year for a certificate and it looks like they'll do it for you. Depending how you value your time, the latter could be the better option.
You could also consider moving to one of the many other shared web hosting providers where automatic SSL comes for free.
At the end of the process you'll have your updated certificate (fullchain.pem) and private key (privkey.pem) files which you can send to your web host.
Other community members may have other suggestions.
Other than running certbot with the dns-01 challenge, either manually or using an API, I can only think of another option: use the http-01 challenge, with --manual-auth-hook to upload the challenge file via FTP.
Those 3 files are standard and could have been obtained with any suitable ACME client that you can run on Windows.
The instructions I provided in my previous post will also produce those certificate files (though they'd be called cert.pem, chain.pem and privkey.pem, respectively).
I couldn't tell you exactly what process you followed the first time, but you can use any program you like, really. They mostly all end up with the same result.
I'm a former developer... why are different names used for what's (apparently) the same file? How can that work?
So I either used a website or downloaded something onto my PC? I haven't used the shell on my hosting service in years so I don't think it would have been there.