Computer obstinacy

I do not know what is going on but my computer is being a little obstinate.  Specifically, the mouse is being obstinate.  I am having difficulty blocking to copy and paste.  Sometimes, it works just fine. Sometimes, I can only get part of what I want to block, and sometimes, I cannot get the mouse to respond so I can block anything.  Other times, I can block everything.  Which is what I do, and after I copy, just delete what I do not want, which is faster, sometimes, than re-typing everything.

Oh well, my computer goes through these episodes of quirks that I am used to adjusting to, and then they go away, and things return to normal.