Finally, trying to instal my PS2202 as a PS3000 did'nt work, so using XP device manager I removed the faulty device, reinstalled PicosCope 5.12.7, Selected the driver manually ("Don't search. I will choose the driver to install", "Select a hardware type, and then click Next")
The hardware types available shown PicosCope2000, so I selected it ...and got it working at last !!!