|There are many reasons why you cannot get full capacity on the drive but without information on your system we could be here all day guessing as to which one it is.|
The most likely is that you have come up against the 32 bit LBA limit. To use a hard disk over 137 Mbs you need both a BIOS and operating system that is 48 bit compliment.
Windows XP with SP1 or later will do it for the Operating System. What about the BIOS?