(Spyder dev here) You have two options to make your console back (that's the right name of what you called as output window :)
Go to the
View
Menu and there from toWindows and toolbars
and select eitherConsole
orIPython console
.If this doesn't solve your problem, just open a Windows terminal (i.e.
cmd.exe
from theStart > Run
Window menu) and in it run this comnmand:spyder --reset
and then restart Spyder again. That should solve your problem for sure.