Nokia :: E71 Shuts Down Automatically

My E71 started giving me a new problem since the last few days:Firstly, I was not able to charge the battery. I succeeded after fiddling with the charging point, there were flashes on the screen, but it resumed charging.I was not able to start up the phone - pressing the power button didn't seem to work. Even taking the battery out and re-trying was like a trial and error method. It works, but I have to try more than once.The phone switches off automatically. If there is movement, e.g. walking with the phone in my pocket, it is definitely going to be switched off.If the phone lies unused for a relatively long period of time, e.g. 30 min, the power saver screen hangs up and I have resort to taking the battery out and follow the entire process.This seems to have started all of a sudden without any prior warning. I shall be grateful to anyone who can help me address this problem.