Follow these steps:

Internet Explorer 6;

• Select Tools.
• Then Internet Options
• Select Advanced from the menu.

Internet Explorer 7:

• Press the "ALT" key to reveal the tool bar and menus. 
• Select Tools.
• Then Internet Options.
• Then Advanced from the menu.

In the advanced options select the following:

• Disable Script Debugging (Internet Explorer)
• Disable Script Debugging (Other)

Click ok, reboot the computer and check to see if the problem has been resolved.

If this does not address the issue you may need will need to run Microsoft® update and make sure you check the "Software Updates" that are available, not just the critical updates. Download and install ALL updates relating to the .NET Frame work.