Problem with closing windows

Earlier today one of my internet windows will not close so I had to
press ctrl + alt + del to close it. Then after it was closed I opened
another windows and everything was fine until I tried to close it. It would
not work. I can't minimize it or make it smaller. I also can't press
on the right key to press close on the taskbar. The only way that I
could have closed any screen was to press file and close. On the internt
windows I had to press alt and then file and close. Did I press something
that caused this to happen?