I have completely messed up my lightroom catalog...

I actually messed it all up a few months ago, but I just use ACR at the moment. I am only a hobby photog, and I didnt really use keywords etc, so it wasnt the end of the World to me , but only a bit of a pain in the ass.

I had bought a new 1TB external drive and cut and pasted all my photos from the C drive to the new external, and another external I had purchased a few months before. I cant remember what I did, but Lightroom could not find any of the photos once transfered. I couldnt sort it myself, and gave up.

Now I have decided that I want to use Lightroom again, so I am asking for advice as to how to get Lightroom to sort my photos. I guess about 12,000 in total, all on 2 external drives.
Do I delete my old catalog, or what should I do?How do I tell Lightroom to catalog my photos?
Thanks for any help
Ben

When you open your catalog with the missing photos, Lightroom should show some red question marks in the Folders panel in your Library module. If you right-click on one and tell LR to locate the missing files/folders, it can either search for them on all your drives or you can browse. Once it finds some on a drive it should then have that drive recognized and will quickly find the others.

The other approach is more time consuming, but if the first approach doesn't work you'll need to do an Import from files and folders command, and step through the Import options and process.

Thank you Tony, I will give it a try.
Ben

And, for anybody who comes across this thread who is thinking of moving pics from one drive to another, the key is to do it within Lightroom. Here's a good source of help.