You need to update the file location in Lightroom Catalog since you have changed the name for the external drive which contains the original images.
Right Click on the folder >> Click on Find missing folders >> Browse it to the Original folder in the external drive.
Please refer the link :How to find missing photos in Photoshop Lightroom
Let us know if that helps.
I am using LR 5. I have tried to change the title of my external hard drive. When I do, some of my photos can not be located in LR. Is it possible to change the title of my external hard drive or do I have to keep it as is. I can find the photos and reenter them in LR if I have to but it will be a lot of work. As it stands now, many of the photos are showing up with the exclamation mark on them. Thank you for your help.
You seem to be making extra work for yourself. It is so much easier to not change the disk name, and then you have none of these problems.
But if you must do this extra work, the instructions for reconnecting Lightroom to the actual photos are here: Adobe Lightroom - Find moved or missing files and folders (see Figure 4)