1) Does the computer see the ext case as a USB device?
2) Does the Windows Device Manager see a HD inside the USB case?
3) Have you set the ext HD as a Basic or ? ? HD? (I forgot the name)
New feature for removable drives.
4) If you can see the HD will it quick format?
5) If it formatted have you created the partitions?
Once all of that is done it should be able to read and write. Unfortunatley the external HD I just added I formatted inside the PC so I don't know if there are any more new fetaures since the last time I installed a new drive.
There was one quirk I heard of. Some SATA drives/MBs had a quirk where you had to install a jumper on the HD to make it SATA I to do the initial format. One of my PCs has this annoying feature so I found out the hardway. The SATA case may hae the same quirk. Google forcing SATA I on SATA II drives to find out the jumper position.
If it turns out you have to format internally, places like meritline have 2.5 inch connector adapter kits for $5-10 to use with laptop drives in desktop PCs.