Unfortunately, the application is developed to run only on Windows 95, Windows 98, Windows 2000 or Windows NT4 platforms. In order to run it on your Windows 7 computer, you can try the Compatibility Mode. Right click on the program icon and go to Properties > Compatibility tab. Check the Run this program in compatibility mode for box and select a compatible operating system from the drop-down list. Click Apply and then OK. If it doesn't work, go to Start, type cmd and open the application using Administrator rights. Type regsvr32 /u pvdt40.ocx, press Enter, type regsvr32 /i pvdt40.ocx and hit the Enter key again.