It started a few weeks ago. When left clicking mouse and also sometimes using keyboard keyboard, a right click menu pops up. Mouse is a Logitech M100, USB wired optical, and keyboard is a HP KU-0841, USB wired. It doesn't happen all the time, just enough to be annoying.
Things I've tried:
Virus scan with MSE - nothing found
Plugging into different USB ports
Cleaning
Checking Device Manager - no problem indicated
The mouse is a few years old and the keyboard was given to me and had worked okay until this started. I hesitate to buy new peripherals for an old system, it would like buying new equipment for an old car you're thinking of trading in. Any other advice appreciated. Thanks.