I have a LTR-48125W that will only give UNKNOWN when scanned with Smartburn. I have tried several discs including ones which I know what they are like TY and Ritek.
WinXP Pro is the OS. The only recent changes made to the system is I updated ClonedCD and installed a clone drive. I had to dump the clone drive as it did strange things with ClonyXXL.
I also installed the trial of Blindwrite suite and allowed it to load some other recommeded drivers.
I have tried older restore points with no success.