If you have an old analog TV tuner card (like those from Hauppauge or Leadtek), modern software often won't recognize them. WinDVR 3 was built specifically for that hardware.
An integrated schedule to help users find and record shows. windvr 3 download
Since InterVideo no longer exists as an independent entity and the software is "abandonware," finding an official download link is impossible. Most users turn to archive sites or software repositories. Important Safety Tips: If you have an old analog TV tuner