If you want to install Pwershell V2.0, one of the requirements is to uninstall previous versions of Powershell. If you don't do that, while installing V2.0, you will get message about uninstalling it. And the message does say to use Add/Remove Programs to uninstall it. So I went to Add/Remove Programs panel and could not find it there. That was frustrating. So I decicded to do some manual search about this installed program. All programs installed on Windows (if done right) have a registry entry at HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall location. If you search on that node for Powershell you will find a key for KB926139-2. Look at value for ParentDisplayName. It points to Windows XP - Software Updates. When we goto Add/Remove Programs control panel, the check box for Show Updates is usually not selected by default. So check that box and you should see all updates. Now you will find Powershell installation under Windows XP- Software Updates (depending on operating system you are using. You can now uninstall it from here. Following screen shot shows registry entry from my machine.