Tente redefinir as configurações do Internet Explorer:
To use the Reset Internet Explorer Settings feature from Control Panel, follow these steps:
Exit all programs, including Internet Explorer (if it is running).
If you use Windows Vista or 7, click the Start button. Type the following command in the Start Search box, and then press ENTER: inetcpl.cpl
The Internet Options dialog box appears.
Click the Advanced tab. Under Reset Internet Explorer settings, click Reset. Then click Reset again.
When Internet Explorer finishes resetting the settings, click Close in the Reset Internet Explorer Settings dialog box.
Start Internet Explorer again.