Barbara, it sounds more like a browser problem than a Renderosity problem. If you are using Internet Explorer (IE) from Microsoft, do the following:

Pick Tools -> Internet Options  and on the "General" tab pick Settings and mark "Every visit to the page".

Click  "OK" at the bottom, click "OK" again.

After this procedure, close Internet Explorer and open it again, I hope it solves the problem.

Piet Vermeulen, South Africa