I uninstalled the Exchange tool wrapper for Virtual PC but the new tool still thinks it's installed. What can I do?

Q: I have downloaded the Virtual PC's but when I uninstall the Exchange tool wrapper and try to install the newer version it tells me that I cannot and that I must uninstall the old version which is already done.
A: Delete the following key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{Random GUID of the program that relates to the V1 of the tool}