IE/Windowsupdate problems

I have a few machines I can’t seem to run Critical Updates on – one of which is my workstation. The updates would download and “install” but all of them (11) would show up in red and say they failed.

I read on a discussion board about removing the root certificate for Microsoft and letting it reinstall. After trying other things (yes, I have local admin rights) I removed the Microsoft root certificate. I was expecting to be prompted to install a new certificate when I went to the updates page, but instead it just fails and says “Software Update Incomplete.”

1) any suggestion why the updates won’t install

2) any way to reinstall that microsoft root certificate? (reinstalling doesn’t seem to help).