Tested by auto electrician. POWER DISTRIBUTION BOX CONTROL MODULE was bad that takes the power from the battery and passes on. Not sure how exactly is this module different from the fuse box next to wheel well.
The very first thing to do with this is get your battery checked. Then if bad, replace it. Then when you have a working battery, check the charging system. Make sure all battery and charging system cables are cleaned and not defective. This can not be diagnosed until these steps are taken and done properly. It may even solve the problems.
If this happened right after you re-cased your key then the most likely possibility is that you have damaged the transponders antenna on the pcb. They are very fragile. Generally the keyless entry portion is separate so it may still be working even tho the transponder is not.
I'm not all that familiar with Peugeot's since we do not have them in the states ...
None of the provided answers are specific about programming a replacement PCM to a 2000 Mazda MPV so I wanted to chime in for any future visitors needing help.
There are two things that need to be matched up when changing this PCM.
1. The engine calibrations (software that runs the engine)
You can usually buy the same part number computer with same software ...