The issue you described is an Internet Explorer misconfiguration or damaged files problem. I suggest you reset your Internet Explorer, reset IE's security zones and sites, and if the problem persists, re-install IE7 or IE8 (It is safe to install IE 7 on top of IE7).
IE7/IE8
Reset IE Security Zones - Inside IE, Tools Menu, Internet Options. Click the Security Tab, then click the Reset all zones to default level. Then click the "Trusted Sites" Icon. Click the Sites button and remove everything that you haven't specifically entered with valid cause.
Full reset of IE (Includes the reset of IE Security Zones)
Inside IE, Tools Menu, Internet Options. Click the Advanced Tab, then click the Reset... button atthe bottom. Confirm by pressing the reset button in the new dialog box that appears.
Downloads
IE 7IE 8