Computer acts weird

Hey guys,whats up?
So recently i’ve borrowed my computer and since then it acts really weird or my mouse does idk.
However when i klick on something it often doesnt react anymore or i have to hold my mouse button down so it reacts,also when i have two windows open and i close one it closes both windows.
when i cklick on a picture to zoom the picture automatically gets marked in blue too.
or when i delete my email and check the boxes the website get marked in blue.
its really annyoing now since it is fucking up my work,any ideas on how to solve?Java etc is already updated.
Thanks :)take care.cya

It maybe that a button on your keyboard is stuck on active. Shift for example.
Just a guess.

I had a problem with a lagging mouse once, I found the usb port was faulty.

I’ve had three cheap mice that did that. What was happening with mine was that the button was simply wearing out. I’ve had 1 color mouse and two Onn mice. The Onn mice would be good if not for that button problem.