The JVC GZ-HD series were great...

Low compression, high quality, high definition video but *not* AVCHD. A good example of why the media does not matter - it is all about the electronics. Those TOD files need to be converted.

Read the camcorder's manual:
http://books.jvc.com/Download/1053651773/LYT1789-001A.pdf
This can be treated like a miniDV tape based camcorder.

Camcorder off. Connect the camcorder's i.Link (not USB) port to the computer's firewire port (not USB) using a firewire cable (not USB). Launch the video editor - I *think* even MovieMaker - and under file, import or capture the video. Power up the computer if it is not already on. Power up the camcorder and put it into Play mode (Page 20).

In the manual, Page 12 and 13 identifies the i.Link port on the camcorder - item 17 in the illustration and the list. i.Link, DV, IEEE1394 and firewire are all the same thing. USB is not firewire. USB-to-firewire cable/converter/adapter things will not work. Item 17 - the i.Link port - refers us to page 49 discussion connectivity to a firewire equipped VCR... disregard that... the "VCR" will be your computer.

You told us nothing of your computer. If it does not have a firewire port, hopefully there is an expansion slot so you can add one. They are inexpensive. Belkin and SIIG work pretty well. I've never had good luck with "Dynex".

If the importing over firewire is not possible, then you will copy the TD files...
If you choose to use the USB connection to copy (not import) the TOD file type video files from the camcorder to the computer, then you will need a transcoder to convert the compressed files in the camcorder to something the video editor will deal with. MPEG Streamclip from www.squared5.com can do that - there a bunches of other transcoders out there. Some good - others not so good.

Do not plug the firewire cable and the USB cable into the camcorder and computer at the same time. Only one cable plugged in at a time... You probably also want the AC power adapter plugged into the camcorder and a known working power outlet...