I've a problem with my Samsung GT-S5610 myself. I had a problem where I couldn't send SMS (now I know it was a temporary problem of the server of my provider, argh). Not being a real genius myself I thought 'well, maybe reverting back to the factory settings could help'.
So all I did was a factory reset but it just didn't finish and after 2 minutes or so the phone resetted. Unfortunately that is all he does now: starting up (Samsung GT-S5610 appears) but then the light of the dashboard go out and the phone re resets itself, and then it starts up again and this keeps repeating itself on and on and on.
Is this the S5610 restarting problem you mention above??
Could flashing be a solution? I don't know anything about it and what could be a problem is the fact that I don't think I could get into download mode (something with volume down + menu button + power??) And if I flash it, will I still have European language options.
Could you maybe revive my mobile? I am so fond of it.