Remote Desktop

I downloaded Microsoft's Remote Desktop client for the Mac, and it installed an application in my Applications folder. It was named "Remote Desktop Connection," and I renamed it to "Remote Desktop." The next day, when installing updates, I think I noticed something about Apple's remote desktop software being downloaded. After installing my updates, that one included, I noticed the icon for Remote Desktop had been replaced with a generic application icon. When I double click it, it prompts me for my password. When I enter my password, it asks me for a serial number, saying it came with the manual from some remote desktop software I don't have. When I leave it blank or enter random numbers, it says it's invalid. Can anyone tell me what's wrong and/or where my Microsoft remote desktop client went?

Don't rename app bundles or disasters like this can happen. It sounds like it was overwritten with an update for Apple's Remote Desktop which you didn't have installed. It also likely asked you for a serial because you have to purchase ARD.

Reinstall RDC but don't rename it.