typing on its own

Hi everybody I couldn't find a solution for it anywhere. I got a problem with my PC. Sometimes, my keyboard or rather the PC types stuff by its own. It's usually just the most used keys (like QWERASDF, TAB - keys used for gaming) but there are somehow moments, where it types in MY PASSWORDS...

Hello. Today when I was cleaning my bluetooth logitech keyboard I forgot to unplug it when I was cleaning near F5 to F8 keys and the keys under. When I realised that I quickly unplugged it and cleaned it. half an hour later my pc starts retyping words I wrote on an essay 2 or 3 days prior. It...