You say that IE8 is not compatible with your employer's software. Can you tell us more?

IE cannot be removed completely and can only be uninstalled to revert to a previous version of IE if a previous version exists on the system. If your system came with IE8 already installed I am not sure you can uninstall then install an older version.

This Microsoft Bulletin tells more.

If you read that bulletin you will note that IE8 has a compatibility option. Have you tried that?

I hope that helps.