I have had this problem from time to time (Windows 7, Explorer) but it always occurs when I am trying to add my e-mail address to online customer information forms (e.g., technical support forms). No matter what key combinations I press, I sometimes just can't get the "@" symbol to appear (usually a " appears instead). Every time this happens, the only solution to date has been to to close the form, exit the form and the Web-site, enter the site again, and re-enter the data. It's a bit of a pain, but on the second try, it always works. I believe this problem lies with the Web-site's form, not with my keyboard or software.