My riocar has been freaking out lately. I think it is a hardware issue, as it was working fine, and I haven't update the firmware lately. After working fine for about 15 minutes, it will start to stutter. It seems like it will play about a half second of audio, then pause for a second, over and over. At this point, the unit is locked up. It will not respond to any buttons, and the only way to shut it up, is to take the unit out. When I stick the unit back in, it displays the "No Hard Disc Found" message. I then need to wait about a hour before it will boot up normally. I upgraded the hard drive from a 10 gig, to a 30 gig Toshiba. I am going to try the old drive in it to see if that makes a difference. So this brings up two questions. Has anyone had these symptomes, and if so, what was the problem? Since I upgraded the hard drive, am I out of luck as far as warranty, even if it's a non-hard drive hardware issue? Thanks.