Strange folders appeared on my desktop

Hello, I have 2012 Mac Mini that is running El Cap 10.11.6. Recently I noticed that a large number of unfamiliar folders and files have landed on my desktop. Adding screenshots below. In any event, overlapping w/ the arrival of these files -- although I don't know if it is related -- the computer has slowed down a bit, has required more frequent restarts, and my Chrome browser has periodically gone through periods of frequent crashing (right now it seems stable.) I would very much appreciate any advice as to what to do w/ these files and folders and if anything else needs to be done? Thanks in advance. JG