Problem with "t" key

Hello,

The problem with my brand new Dell is that sometimes while I'm typing several sentences, the "t" key will trigger another window to pop up and it will finish the word in another window, or it changes the font or italicizes everything after the "t", or it has been closing the window altogether without warning. This happens in several different programs on my computer: internet explorer, mozilla firefox, and microsoft word. I just talked to Dell, and they suggested it was a problem with my operating system (Vista), and to restore everything to factory settings, but that just doesn't seem like it would fix the problem. I appreciate any suggestions.

Thank you!