Weird pc problem

[Scarlett]

When I am typing anything online, such as on here, I get a internet explorer box appear, followed by the scroll symol (from the mouse) and then the page disappears!! It is infuriating. It is like it is trying to place a short-cut or something. Any idea what is causing it and how I can fix it? The box is the one that says UNDO, CUT, COPY, PASTE etc

[Scarlett]

Also when I am typing an email, another box appears, and the cursor jumps backwards to earlier in the email, so I end up writing in the middle of an earlier sentence! Aaargh! Any ideas?