Your system is somehow corrupted, could be music downloaded from the net, whatever it is easy fixable.
A) Download the firmware from Archos and save it to your desktop (Make sure the file name on the desktop hasn't changed from the original download file name)
B) The Archos 5 or 7:
1- Plug the unit to you computer via the USB cable.
2- The unit should start automatically and open the following page:
3- From the recovery console (the screen that asks for repair or format etc…)
4- Select "Repair"
by scrolling up and down with the volume control on the right of the unit (Do not press "Format"
at any time)
5- Now that you are on "Repair"
press the on and off button, shortly to validate your selection
6- The unit will go to "Plug the unit etc…" but it is already plugged from point 1 - DO NOT press anything anymore on the Archos
8- Wait until Pc should recognizes your Archos (around 5 seconds)
1- From your computer select the firmware file you downloaded from the net and put it in your Archos (in the root folder, nowhere else, where it has the folders, music, videos, pictures etc… as a file)
D) On the Archos 5 or 7
1- Select "Ok" on the Archos (on & off button) shortly to select and confirm the file is now on the Archos
2- you are done! The Archos 5 or 7 should now read through the file you have transferred and repair the system
3- DO NOT DISCONNECT the USB cable until the process is finished
4- when done safely disconnect (as you usually do, for Mac trash the letter of the Archos to the bin or for PC's: right click the green icon bottom right of the screen for xp & vista)
5- Press on/off button to reboot
Your unit should restart with a fresh repaired, updated system like day one.