Can anyone help with a freezing problem please?

Start 20, bog standard unit running 840.2562 UK maps. (bought for 20 pounds)
After turning on you set it up, and every time it gets to the set clock page it freezes when you press 'done'
After several seconds it reboots, and continues in this loop.

I have tried the V9401 hacked navcore, I've connected to Home and it upgraded to 9.02.
I have tried the flash clear tool some 10 times.
I've formatted the internal memory (both FAT and FAT32)
I have tried newer maps and the newest maps.
And any combination of all the above!

The maps patch, the system patches and everything seems fine, but when you disconnect and reboot it freezes at the set clock page.

Any idea's?
Thanks, Bob.