Logically, if I was working fine and now it isn't, and it also doesn't work on another PC, then it must be broken. If you haven't done anything to break it and it is only a couple of months old, then you should be able to get it replaced. If you have problems dealing with the retailer, then the manufacturer may help you if you explain that the seller is not playing fair.
I did have a look for the US version of our 'Statutory Rights' but didnt have much luck but then you will call it something else no doubt.
Good luck
