I need to find files from my old computer (now saved on an external drive) so I can complete editing and use the photos for a project. How do I do that without losing the work I have already done on those photos? I have a new computer, and a newer version of Lightroom.
That is a very good tutorial. Installing a newer version of Lightroom on the new computer will involve Lightroom creating a copy of your old catalog that is compatible with the new version. But it should be very painless.