Replying to Getting into filming

i'm about to get my first camcorder and i had some questions:

what kind of computer do i need to transfer/edit MiniDV movies? Will new computers all be compatible?

Once i've used up a miniDV tape, can i transfer it to the computer then erase it and re-record on it?

If my computer isn't compatble how can i install the neccasary stuff? How much does it cause?