My nokia e61 goes off all by itself after some time say 2-3hours

You can get the Unlock code for NOKIA E61 model Phone at
Onlinegsmunlock.com and Unlock it from network lock easily.

Nokia E61 is a business phone and is specially made to work with business applications.But your present phone is a true multimedia phone made with giving importance to multimedia applications.

Full working!!!!
I solved SMS sending problem with E61

Just hard resset your NOKIA phone by pressing in same time this four buttons:
1) * (star) button
2) 3 button
3) green tab (call acceptance ) button
4) power on - button

NOTE Press all this in same time and wait until phone load.

read this post of a specialist:
http://thesymbianblog.com/2008/07/11/rant-nokia-your-firmware-update-apparatus-needs-a-serious-overhaul/
it won't solve everything, but it will confirm that the nokia firmware update is very buggy and... you should complain at Nokia!

To install themes, and other applications, onto the Nokia E61 you will need
to download and install Nokia PC Suite on your computer. The program is
free and available on the Nokia Web site.

Once the program is installed the cellphone must be connected to the
computer through a cable, Bluetooth, or infrared connection. The PC
Suite program will guide you through the process. A cable connection
is the fastest.

PC Suite has an application installation manager. Use it to install
any themes or Symbian 60 programs you have downloaded. Once
the theme is loaded on the cellphone, use Menu > Tools > Themes
to find the theme name. Click on it and the phone will ask whether
you want to preview the theme or actually install it.

I have the same problem too. The backlight won´t work. Is there a way to fix the backlight by substituting it?

wow, that is something... have you tried reseting it back to its factory settings?? it is an option available in the phone itself.. you dont need any secret pass code or stuff. It should fix the problem.

I had this problem once. My problem was due to a file (currupted) in my memory card. I found this out by restarting the phone without the memory card. once the phone was up and running, i looked for the damn file and deleted it...

You should download the patch from the Nokia Europe website for SMS for the E61. This is recommended for all users, as it will significantly increase the speed of sending messages. Vir