It seems you have created quite a bit of a messy situation.

Since you have 66 lrcat-files, i.e. 66 different Lr catalogs, none of them would be a good starting point - because every one of them does not completely reflect your images.

The question mark that you are getting on the frame of the images is n indication that Lr does not "know" where this image is. In this context it is important that you know that Lr is not a browser based program. A browser based program "sees' whatever files are on the hard drive. Win Explorer is such a browser based program par excellence. But Lr is different; it "sees ' only those images that have been imported. When they are imported, Lr stores also the location of the images in its data base (= catalog). When youthen move or rename images outside of Lr (for instance in Win Explorer), the situation on your hard drive is different from what Lr has stored in its catalog. Then Lr sends you a "?" as an indication that it can't find the image.

In this situation you have basically two options:

a) Take one of your 66 catalogs as a base and try to reconnect your images;

b) start fresh at point 0. This option would have the consequence that you would loose all the edits that you did in Lr, and your images would be in the state they were in before you imported them into Lr for the first time.

Let's talk about option (a):

You said you found 66 lrcat files. You can right-click each one in Win Explorer and select <Properties>. This would give you the dates when the file was created and when it was last modified. You have to select the lrcat file that has the most recent date of modification as your basis. Select all the other lrcat files and move them out of the way: Create a folder named <Old Lr catalogs + date> on your C-drive and move all the other lrcat files in there (Win Explorer > Edit >Move to folder).

Now double-click the one remaining lrcat file and Lr will open with it. Do not use the import function, rather proceed as follows:

In Grid View in the folders panel (left side) you will see "?" besides the folder names. Right-click a folder and select <Find Missing folder>, navigate to the location where this folder is now and click on it. You can do this for each folder separately, or if you have a structure of sub-folders under parent folders, you can do this <Find Missing folder> procedure for the parent folder and Lr will find the sub-folders on its own, provided that their names have not been changed. If you did change them you will have to do the <Find Missing folder> for each individual sub-folder, too.

If - after you have reconnect Lr to all the folders - single images still show question marks, you have to reconnect these images individually. Left-click the question mark directly and select <Locate>. Then navigate to the location of this image and click on it.

You see that this procedure might take quite a bit of work and time.

That's where option (b) comes in. But, as I already said if you go this route you would loose all your edits and everything you did so far with your images in Lr. You would start all over again. Here's how it goes:

Close Lr. In Win Explorer organize your image folders to your liking. Give them any structure and names - but one thing is important: You have to put all image folders into one (1) parent folder. Name it <My images> or whatever you like. You can put it into the <My pictures> system folder or you can have it separate from it.

When this is done find all your lrcat-files and move them out of the way (see above).

Now open Lr. Since Lr will not find a catalog it will open the Import Dialog (where it says source on the left side). Select the images parent folder as source and import your images.