It is possible that a keyboard/mouse driver glitch occurred. Holding down the Ctrl key while scrolling zooms the page in/out, clicking a link opens it in a new tab, et cetera. You should still have been able to access the Restart options, but if the glitch involved another key being virtually pressed, it could cause that too. If the problem does not continue after rebooting, I wouldn't worry about it. Otherwise, you may consider reinstalling the latest drivers.

Hope this helps,
John