FOR SOME REASON I CANNOT SEE ANY DOCUMENT'S PREVIEW PANE. OPENING THE DOCUMENT IS NO PROBLEM. ANY SUGGESTIONS ON HOW TO SOLVE THIS ISSUE? tHANKS.
Your caps lock key appears to be down.
Which kind of documents are you having problems with?
Do they display OK in File Explorer's viewer pane?
If they are PDF documents, try reinstalling your PDF viewer (e.g. Adobe Reader).
If they are Word documents, try repairing or reinstalling Word.