Help with 8210!

HI, My mate recently bought an 8210
The phone powers up ok but after a while it will either reset itself or just turn off.
As far as I can see there is no water damage to the board and I have flashed it with a new software version updated FAID IMEI etc.

Has anyone else experianced this and fixed it??

Thanx in advance!

I have just tried flashing it with the software from my phone and tried it with my battery etc. but it still resets!

This must be a hardware problem so which part is it???
And how do I fix it?