The DCR-TRV30E is a digital camcorder but the USB connection is not supported in Vista or Windows 7. You will need an iLink/Firewire cable to transfer Video to your Windows 7 computer. No drivers are required and you can import into something like Windows Movie Maker.
The CCD-TRV300E is fairly old now and records onto Standard 8mm or Hi8 tape. The recording is Analogue (Composite Video or S-Video) and is older than more recent digital models. You cannot transfer the video using a modern USB or Firewire digital connection.
How are you trying to connect to your Windows 7 computer?
You need an Audio/Video Cable and a computer with Analogue Inputs. Most Windows 7 computers do not have analogue connections, so you may need to buy a digital video capture box to convert the signal to digital USB like this: -