want to show desktop icons

ok i want to show my desktop icons and when i right click on the desktop ,
nothing comes up. earlier today, i right clicked and by mistake , had
unckecked the option
to show icons. somewhere in the computer is a way to check the option: show
desktop icons.
2} another problem is an ad that is stuck on my desktop about adware and it
won't let me change the walpaper. ok somebody please help. thanks. donald c.
561-304 1384 wpb , fla