This morning I can't see any men or positions in any of my games, just a blank board. Is this a temporary problem with the site, can you tell me, or with my computer?

We have been asked by admin to use the 'report bug' link at the bottom of every page for this kind of issue.

Try clearing your browser cache. There are steps for this here: http://support.chess.com/index.php?_m=troubleshooter&_a=steps&troubleshootercatid=1&parentid=0