In the end, I discovered that it's not just the mouse that was problematic, it was the receiver as well. In fact, maybe it was just the receiver at fault, and it lost its capability to decipher the signal for a mouse click.Anyway, I bought the same set again, because it's the only cheap wireless 75% keyboard I could find on the market. By way of curiosity, I did try to see if the old peripherals work on the new receiver, and there was no success. Each set is hardwired (hardwirelessed?) to its own receiver, so as not to interfere with other sets that may be nearby, and encrypted for security. The manual doesn't even make mention of pressing the CONNECT button for pairing ... it's very much plug and play.Thanks, both of you, for your time.