Robert Swinney wrote:

Upon boot-up the message, "Error - Program version is wrong. Please install again." This in my win
XP desktop. A casual search seems to say, somehow, that Windows Installer is missing. The
suggestion: StartRun register with "msiexec/unregister" and reregister with "msiexec/regserver".
Each/either leads to the message: "Windows cannot find msiexec/******. This began happening
following attempted upgrade to 2010 DVD of mapping software. Suggestions ??

Bob Swinney

Restore from backups.