There are several things that could be preventing this. If using Internet make sure to try enabling compatibility view. Also make sure your display drivers are up to date and download the latest flash player. Also for Internet explorer try this, 1.Open Internet Explorer by clicking the Start Button. In the search box, type Internet Explorer, and then, in the list of results, click Internet Explorer. 2.Click the Tools button, and then click Internet Options. 3.Click the Advanced tab. 4.Scroll to the Multimedia section, and then select the Show Pictures check box. 5.Click OK. Also you can try this un-check "Use DNS pre-fetching to improve page loading performance." = to do this got to "settings" (wrench icon") > Options > Under the hood.
Sometimes browser extensions/add-ons can cause problems. For example the Chrome extension called AdBlock can be the culprit. Try disabling add-ons one at a time and see if it fixes the problem.