On the basis I can think of no logical explanation for the fault, I'd tend to recommend you take it back to where you bought it from. You say you bought it recently, so I assume it's still under warranty.
I've just had one thought, though, and my apologies if it insults your intelligence. You talk about logging on, so I assume you're entering a user name and/or password. In which case, are you sure that you're positioning the pointer in the box where you want to type, and clicking in it before you start typing? It could be that the logon 'box' isn't active from the start, and you have to activate it by clicking in it. Not doing so would give the symptoms you describe.