Thanks for the input. I tried the recommendations - no joy. So I formated the SD card as bootable, using cardtricks and reinstalled CHDK. On the boot I get the CHDK logo and battery/memory display enhancements, but I cant access the CHDK memu. My camera has no "Print" button, but the documentation says for SX100 (mine is SX120) use the "Disp" button (which I have then menu ), but alas no CHDK menu just the nnrmal Canon menu.
Any further ideas?
Again, many thanks...