the av300 is dead easy to replace the hard drives. rule of thumb though.
get a 5600rpm MAX speed (there abouts) not the 7000rpm as they make the players walk though vibration, an 8mb or 16mb cache drive (or bigger) can save battery life as well!!.
i think the original hard drive was a hitachi - ive never had any joy with those drives - always failed just past warrenty for some reason......
a pata (small laptop size ide) drive is the one you want not an sata.
here is a walkthu someone else put up years backhttp://www.dvrplayground.com/gallery/16 ... by-Glenn-L