Firstly, Thank you Russell, Erik and everyone that takes the time to read all these posts.

Erik, I now see what you mean by differences in the ground line.
I measured with the ground of the scope on my board and the probe on the common ground of the switches.
On every switch closing I find a 4 to 16V ptp spike in the ground line. the period being 150ns.
I also find spikes on the ground line everywhere in my board on the closing of the first switch. for this measurement, I connected the ground of the spike on a 5V ground of the board and placed the probe on other ground pionts on the board, these spikes were max 8V ptp.
I also find these spikes on the Reset line of my micro. this line was supposed to be 0V.

Again, thank you all for your time.
sun.

ps. when I said charge pump in my last post, I ment something like a Potential Clamp at a particular potentioal, sorry!