I think my computer is haunted. I've spent several hours examining it today, and here is a small sampling of what I've encountered. On any webpage in Chrome, typing Ctrl+C like you would to copy something is interpreted as typing "". Ctrl+V, used to paste things, is interpreted as "". Backspace isn't recognized as being pressed at all,* but if I hold Ctrl down, it functions as the Delete key. If I open the same page in Firefox, no keys work *unless* I hold down Ctrl, then Ctrl+whatever works like normal.
And that's just the web pages. Firefox has the same problem if I type in its address bar as if I type on a webpage, but Chrome has something different. In Chrome, if I try to type in a web address, Chrome activates the Ctrl-command associated with any key which has one. So if I type the letter a, it uses Ctrl+A to highlight all text. If I type v, it pastes whatever I last copied. So forth and so on.
*For any programmers out there, the key is actually recognized as being pressed down and let up, it just isn't triggering a keypress event to do anything. I have no idea how that's possible.