How to force a factory reset or hard reset on Archos devices

Archos 101 Xenon Archos 101 Xenon
Archos 70 Copper Archos 70 Copper
Archos 90 Copper Archos 90 Copper
Archos 101 Copper Archos 101 Copper
Archos 59 Titanium Archos 59 Titanium
Archos 90b Neon Archos 90b Neon
Archos 101b Neon Archos 101b Neon
Archos 101 Oxygen Archos 101 Oxygen
Archos 70b Xenon Archos 70b Xenon
Archos 80b Xenon Archos 80b Xenon
Archos 45 Neon Archos 45 Neon
Archos 50b Neon Archos 50b Neon
Archos 70 Helium 4G Archos 70 Helium 4G
Archos 80b Helium 4G Archos 80b Helium 4G
Archos 101 Helium 4G Archos 101 Helium 4G
Archos 45b Helium 4G Archos 45b Helium 4G
Archos 50c Helium 4G Archos 50c Helium 4G
Archos 52 Platinum Archos 52 Platinum
Archos 59 Xenon Archos 59 Xenon
Archos 62 Xenon Archos 62 Xenon