This happens because you have a fake Kingston pen drive and you have exceeded the true capacity of it. The only way of recovering this is to open the case and see what controller you have and how much memory you really have, then find the manufacturers low format routine on the web and reprogram it. Don't expect to get back the original capacity though, your stick is either a 256Mb or 1 Gig one. Return it to your supplier if possible. Google fake USB stick for further info.