It's called analog-to-digital pass-through, which your camera does support. You hook the AV out of the VCR to the AV in on the camera, and hook the camera to the pc with the firewire. You shouldn't even have to have a tape in the camcorder. I don't have your specific camera, but your manual should tell you what settings to change in the camera menu to do this. Typically it is: set the camera to VTR/VCR mode and go in the menu set-up and set it to DV out. Push play on the VCR and play on the camera, and the signal should pass-through out the firewire.
Most cameras do not come with all the cables you need to use all the available connections. You may have to get the proper cables from Sony.
You will also need computer software to capture the firewire input. If the camera didn't come with any, you can download WinDV for free.
You're also going to need a big hard drive. Every 5 minutes of video takes about 1 gig of hard drive space.
Is there a way to port the signal from a VCR through the Sony DCR-HC85 to my computer Without actually recording to tape then playing the tape to send it to the computer ... I dont have a video capture card for the computer just the usb or firewire ports ...