Go to My Computer > View System Information (left bar) > Hardware > Device Manager
Expand the 'DVD/CD-ROM drives' tree and see if there's an Hitachi drive there (or any drive you dont recognize). If there is, right click it, choose Properties, go to Volumes then click Populate.
This should give your drive a letter and it will display in My Computer
Thats what I had to do, I only had to do it once (the first time). From now on, it recognizes it straight away.