Keys not working Of my nokia mobile 7610

I have a nokia 7610 which i have purchased a few months ago. Its in a very good condition. I have never dropped my cell phone any where nor have i ever threw or press my cell unknowingly. My problem is that, yesterday when i was working with my cell, the 4, 5, and 6 digit keys and calling key of my nokia mobile suddenly stopped working. I had switched my phone several times and tried again but again the result was the same. Although the remaining keys are working properly but cant find the solution for this. Can anyone help me out with this.

Try to remove the upper enclosure of your mobile panel, check whether there are any dust particle sticking onto the buttons, if yes clean the buttons with the cloth and check again. If again its working then use a pointed shape stick which can go through the buttons.Try it on the buttons which are not working, if this dosent help you then you have to send it to the shop for repairing it.

I also was facing the same problem with my nokia 7610. Even i had never dropped it nor there was any external damaged to it but then also some of the keys stopped working. After trying several options i finally decided to format my mobile phone. After that the phone started working normally as before and all the mobile keys and function were working properly.

The solution for your problem would be given in the following steps follow this and see if it can help you.
1 Press and hold 3 keys i.e. Green, dial key, *, Star key, no. 3 , key on keypad
2 press the power on/off to switch on the phone
Before doing this take a backup of your data because this steps might lead to loss of some important data.