I have recently purchased an older (4 yo) laptop and am looking to add USB to it. However, it appears to have a slightly different slot than all the available usb cards on the market. I have two cards for it now (class "b" wireless and ethernet) and both of those have a groove on the side of the card that is narrower than the cards I have tried from several different companies. Otherwise, the two types appear to be identical. What do I do? I refuse to give up on it but I absolutly must have USB. Any thoughts? Thanks