First you need to know which version of LR you were using. Download the correct version from here: Install Photoshop Lightroom
If it was LR6, then it is the same installer for LR6 (standalone version) and CC2015 (subscription). The difference is the licensing model and if you have LR6 standalone serial you will be asked to enter it during the install. If you already installed it and it shows as CC trial, here's how to convert: How to convert a Lightroom CC trial to Lightroom 6
The default install always installs the Adobe Application manager as well - I'd not care about this. You may even remove it later if you don't have a subscription..
You do not need the disc to install, use the download - not matter if it is LR5 or LR6 ....
You do have a backup of your catalog and the images, do you?
Thank you. I will try this. Yes, it is version 6. I am guessing that I have to install the manager program in order to complete the download/installation process? Incidentially, when I first downloaded the standalone and it denied the activation serial number, it opened in a 30 day trial. Is this the same thing? Can I convert that back to my regular version? And yes, I run catalog backups every time I use the program. I will let you know if this works
If you have your LR 6 serial it's easiest to enter it during the initial installation.
If not and it runs as CC trial, use the linked How to convert document to change the license model from CC/trial to standalone - there's no re-install needed.