The solution could be rather simple, depending on how you've organized your images. For 'simple', consider this example (Windows):

A, images reside on connected HD labeled "H", like H:\all-my-pics\**
B, you copied this entire "all-my-pics" folder structure onto your C: drive.
C, corrective action is to:

1, open LR.
2, display the Folders in the LR Library module.
3, Find the "old" H:\all-my-pics\ folder inside LR.
4, Right-click that old H: location and select "Update Folder Location".
5, Navigate to the new C: location and <Select Folder>. LR will cascade this update for all the images in the LR catalog.

If needed, repeat the process above for any multiple high-level "entry points" to the organization of all your images and folder structures.