Dell :: Inspiron 1545: Fast Typing In Webmail Results In Missing Letters

I've browsed the discussions and have seen problems similar to, but not exactly the same as, my problem, hence the new thread.

Problem: I have a brand new Inspiron 1545 from Dell online. When I type text in Internet Explorer (e.g. webmail applications or this forum), even at a relatively slow speed, many of the keys don't seem to register --

that is, letters or spaces whose keys I press do not show up on the screen. As a result, I must type verrry slowly to make sure that every letter/space shows up, or else go back to re-type it. Strangely, I do not have this problem when typing text in, say, Notepad .....