kindle hangs and restarts suddenly

Hello,

I am in India right now and my kindle I brought frm London.

It is kindle 3

Lately, Kindle hangs ( unresponsive) and restarts anytime while reading.

I did factory reset with the help of amazon customer service person, but it refuses to be better.

Now it is just lying in my cupboard. I cannot use it. I do not know what to do. I want to avoid throwing it off for the latest of new version as i like the analog system of it very much.

Thank you