Can anyone describe (instruction) how to replace the back up battery?
Best with photos.
What are the things that need to be careful...
Thank you in advance.

I, too, have the same problem.
First, what battery do you need?
Second, is it a simple solder-in solution?

My backup battery is dead and won't recharge. This makes it VERY difficult to use it because I cannot change the main battery.

My MDA is giving me problems with WI-FI and I'm wondering if I should go back to the IPAQ. Plus, I like watching movies on the IPAQ more than on the MDA, and on the MDA more than on an IPOD.

I found a backup battery here in the US for $15 +$3 s+h. I have yet to install it. NOW the backup looks like it's 100% but I'm afraid to pull the main bat and lose it all again. At least it's backed up.