No text displayed in preview mode

Hi all,

I have a problem that has only happened a few days ago. When I preview my presentation (in preview mode) none of the text is displayed in the preview (i.e. the background image and the other images are displayed but no text). However, when I render my presentation everything is there. It's the same for Quizmaker and Engage (i.e. all text is omitted when in preview mode. I have three licences, and use Articulate on three computers - the other two work perfectly. My one (the third computer worked perfectly until a fe days ago). I've reinstalled Studio 13, the flash player and also Chrome browser (just to be on the safe side) but to no avail. The fonts are all installed properly so I have discounted this as a possible cause. I have a nagging feeling that it could have something to do with the way flash generates the preview (as fully rendering to the browser is not affected) but my knowledge of I.T. is limited and therefore I have come to a dead end. I would appreciate any comments/suggestions from the community. Thank you in advance.