I have been upgrading LR for awhile now.
Currently I have LR 4 & 5 still on my desktop computer.
I am currently using LR CC.
What happens if I remove LR 4 & 5?
how can I make sure I don't lose photos?
You can safely uninstall the older versions, if you don't think you'll need them.
It will not affect your photos, they are not inside LR, they are only referenced by the catalog,
You won't lose photos as they are never inside of any LR version. LR is a Database program that References your images from where you placed them on your hard drive. As long as all your presets and settings are working in the newest version of LR you are using you can safely remove, Uninstall, the older versions. You can also delete the older catalog files and the preview folders that go along with those catalog. Uninstalling the LR program does not automatically remove the older catalog files.
thanks for your prompt replies!