Running XP Media Center Edition, SP3. Following some unknown activity by my son, the machine now gets a popup window of "Windows Installer/ Preparing to install..." very often, as much as several times per minute. If you cancel the popup, it just pops up again. It normally does not name any particular program, but on occasion it refers to the Roxio Media Player. 1. In the Add/Remove Programs list, there is nothing Roxio. 2. I have run Spysweeper and PCcillin antivirus regularly with no improvement. I have run Microsoft's Windows Installer Cleanup Utility but it will not run properly, saying that another installation is currently in progress. Help-any ideas? thanks/ Greg.