Strange problem

Thing is that,I have a nokia 7610.My problem is that even there is no headset connected to my phone,the "headset connected symbol" is displayed on my phone.And I can't listen to any voices over the phone during conversation.

Other thing is that,my current profile changes frequently and automatically.I thought it was a virus and have hard formatted my memory card and the phone.But the problem prevails.

I am requesting you all to find a solution to my strange problem