Weird xp problem with LG GSA-4120B

I have just bought an LG GSA-4120B DVD-RAM -R/W +R/W drive and I run it from an Constar firewire / usb 2 enclosure on Winxp home. I decided to use firewire because the USB bus has disks on it. For the first couple of days it worked fine and then it stopped working. The drive name changed to “DVD-RAM Drive” (from “MX-120”) and it always says “Please insert a disk into drive” when you click it in explorer. I tried everything and eventually it came back on after I installed an MS service pack for firewire enumeration. It again worked fine for a week and again stopped working and went back to “DVD-RAM Drive”. The drive information in nero is always okay and the same problem occurs when I use the USB2 connection

What’s going on? I have made no changes to the system but it seems to change when it wants.

Any help will be appreciated.