Moving files from Dropbox back onto PC

Hi everyone. I wish there was a phone number to call for this but oh well. So my issue is, is that many files that were associated with my Student DropBox account became inaccessible on my PC. I downloaded all the files that are stored on my account (resulting in copies of the original files) and the moved the files from the Dropbox folder on my PC to their original places on my PC (in My Documents). The files that I moved from Dropbox back to My Documents are able to be opened now. However, the "original" files that were on the PC still cannot be opened. I wanted to get all the files from Dropbox back onto my computer, and then delete my account. After moving all the files from the Dropbox folder on my PC to My Documents under "This PC", am I okay to delete Dropbox, or is there more I need to do? Screenshots attached for clarity.

Here is a screenshot of the Dropbox folder.

 Here are the original files under "My Documents". The other "My Documents" folder is what I downloaded from Dropbox. The original files have Xs on them and they can't be opened.

Here are the folders and files I moved from the Dropbox folder to "My Documents". These ones are available. Should I delete the original files that are now inaccessible?