Issue possibly due to my PC being refurbished. The old IT dept at the company probably hid/deleted files and MicroSoft certified techs did not fix all the issues.

Solution in 2 steps:
First I added the part of the path that was missing, so to:
User/(user name)/AppData/Roaming/Microsoft
I added: /Document Building Blocks/1033/16

Second, I still could not see the files, but when I saved a NewBlocksProject.dotx file to that folder the Building Blocks.dotx and Buil-in Building Blocks.dotx became visible. So I right click on them and saved them to a thumb-drive. However I had saved my new blocks created in Quick Parts into NewBlocksProject.dotx so added this file to the User/(user name)/AppData/Roaming/Microsoft/Document Building Blocks/1033/16
folder on my second computer and now I have my new blocks available there also.

Note: the show hidden files and folders, is set to "show"