If squares are all grey (or black, or white..), it's usually a monitor profile issue:
(or a video driver issue).
Another possibility is lib-preview subsystem problem, but usually that manifests differently - consider posting a screenshot.
Thanks, also, when I click on the grey preview, it says, file could not be found.
Just wanted to let you know that I'm okay now....I just had to find the original files...must've moved a link or something?
Thank you for your help.