A lot on N97 are suffering from the same prob, mine occurs slightly after the 1 year warranty cover hence I was left alone to salvage the phone. If u have tried new batts (original) or new chargers u will come to know that it's not a hardware prob rather than a software, there a lot of discussion on the nokia forums where ppl have been in search for a solution 2 years ago, but nokia seems to be turning a deaf ear to the complains.sending ur phone to the service centre for a format will not solve the prob rather again a waste of time make u angrier. the phone actualli connects well through the USB cable but just that unable to charge for long which says that the socket is actualli seeking v assume,

I've tried new batts, new charger, reformat the phone, install crap software, trying types of pluggin combi, casting spells, cursing.... Still the prob lies persists.

What I 've yet try is change he charging socket or throw the phone into the bin, but who in their mind will want to spend more money for a crap phone which has been s problematic that even nokia themselves hav given up on it (flagship sum more!!!) it's jus considered bad luck with a crap phone by a crap company. Lesson learned.