Latitude d600/hard drive

Please Help!

I have recently formated my latitude D600 I have a Fujitsu MHT2040AT (40GB) Mobile HDD that fits in the modular bay, before formating i saved all my doucuments to this drive after reinstalling  my o/s windows xp i have no drivers missing in control panel but  i am unable to see the Mobile drive, it shows up in the divice manager and the bios but not in the rest of windows when the drive is removed and replaced with the cd rom the drive shows up straight away and the mobile drive disapears in the divice manager.  i have tried flashing the drive with the file from dell.