Archos 80 G9 freezes 15 sec after boot up

[puzzled]

After working pretty well for almost a year, tablet started freezing occasionally and now systematically freezes about 10 -15 seconds after boot-up. Running most recent firmware (4.0.28?), lots of free storage space (12GB). Seems to function perfectly at start-up -- wireless connects to access point, apps start up, etc. -- and then screen stops responding and have to press and hold pwr button and reboot. Checked file and data integrity in recovery mode, tried turning off wireless, no joy. Can't download files off the device via USB because when it freezes the Archos icon disappears off the computer.

Is there anything else I can try before I try reinstalling the firmware? I doubt it's a problem with the firmware because everything runs perfectly for the first 15 sec -- so what takes 15 sec to kick in? Looks more like hardware to me but I'd be happy to learn otherwise.

Update Dec 11: Situation deteriorated. Can't even get to the recovery mode now -- screen goes blank 2 sec after displaying the menu. It's going back to the Archos mother ship.

Resolution (April 16, 2014): After 3 months at the Archos Illinois facility and several phone calls I was sent a 101xs as a replacement for the 80. Apparently they didn't have (and weren't expecting?) any 80's to send as replacements and they don't do repairs at that facility. I preferred the 8" screen and this is heavier and has a separate keyboard which is not much use (it does provide good protection for the screen). But I have to give their customer service some credit: they were always extremely polite and apologetic when I called, and they did eventually send me a working (upgrade?) replacement. Which is working satisfactorily. So far...