I have had the same problem with ISE (a purches version). ISE now relies on Windows installation services. If the installer sees a previously installed product, it goes into "maintenance mode" and wants you to uninstall the previous before installing the new. If you do the uninstall, you will then be able to install as planned. You will see this behavior even if you want to install to a different folder or different drive. End users report that the uninstall-then-install procedure works OK, but they find it very confusing. I have had lots of other troubles (esp on Win2K machines) with ISE and am switching immediately to the Wise Installation System - a script based installer (not windows install services base). It appears to me that neither ISE nor windows installer services are ready for prime time yet.