Errors installing Microsoft Security Essentials

During the install of Microsoft Security Essentials I was receiving the following errors:

• 0x80070643
• 0x8004FF37

In the end I found a Windows OneCare Cleanup Tool here:

http://social.microsoft.com/forums/en-US/onecareinstallandactivate/thread/399071e2-49dc-4767-932d-d261e3965943/

This machine never had OneCare installed, but as I watched the cleanup tool do its work I noticed it was cleaning up older versions of Windows Antimalware and Windows Defender. This machine did have Windows Defender once upon a time.

For what its worth the Cleanup Tool wanted a reboot, but I declined, and MSE installed successfully.