How can i fix my sonyericsson w810i?

The same thing happened to me. In my case, my power button broke off so I soldered the connection so that the phone thought the power button was pressed at all times. This way if you put the battery in the phone it would turn on but would not turn off until you took the battery out. However this presented a problem. The phone must have thought it was receiving input (pressed down power button) so it wasn't able to handle as much other input. I found your question above becuase the EXACT same buttons were disabled on my phone when I did this. So I guess my response to your question is you might have a broken button somewhere that it "jamming" the phone from receiving input from certain buttons.

Adam
August 2008