But if you must, check with TWEAKUI (see google) to see if drive letters are hidden.
It's possible they didn't install the OS proper so while it's new, why not use the restore media and start fresh?
I have recently purchased a Compaq TC4200 tablet. It has a SD slot on the side so I decided to try it out the today. But the card reader doesn't show up on my computer, and device manager showed a SDA Standard Compliant SD Host Controller.
I am using windows XP tablet edition.