I'm not very technically gifted, so any help would be of use here. Basically on MSN Messenger, halfway through conversation my shortcut for Shift+2 changed, so that instead of giving me a ", I am given the @ symbol. Likewise, Shift+' does the opposite, giving me ", when I want @.
This isn't a huge problem, and it is restricted to MSN Messenger. But I'd like to switch them back, if possible, and maybe someone could tell me how they switched in the first place, because I don't remember touching anything.
Sorry if this is in the wrong place.

Try Alt+Shift. Happens to me constantly.
Perhaps I should just turn that damn thing off...