Recently Microsoft issued an ActiveX update that changes the way in which Internet Explorer handles some Web pages that use ActiveX controls.

The MSHTML.DLL file that shipped with this update however had a serious problem. Here are the steps to reproduce the problem in a test computer.

Important: The following steps are to be done in a test system if you're wanting to replicate the problem.

1. Install Q912945 update and reboot.
2. Click Start, Run and type regsvr32 /i mshtml.dll

Try to open System Restore, User Accounts and other things that use MSHTML.DLL. All the dialogs will be blank, and you'l be unable to use IE.

DllInstall and DllRegisterServer method updates several registry values with wrong data, instead of setting the
full path to the DLL file. This is purely a bug in this version of MSHTML.DLL (6.0.2900.2838)

To restore the functionality back:

Uninstall Q912945 update via Add/Remove Programs applet and reboot. After rebooting once, re-run the regsvr32 /i mshtml.dll command again. Then reapply Q912945 if you need it.