Customer find he suddenly cannot use his vista laptop to read any cd/dvd discs.

I notice that the vista device manager shows the dvd drive (a matshita uj-891S) has a code 39 error.

On the net, some people suggest getting the most recent drivers (but vista believes it has the most recent drivers anyway), and others suggest the MS support page at: http://support.microsoft.com/default.aspx/kb/929461

I start going through the MS instructions, but I see that there in no registry entry for UpperFilters, just LowerFilters.

I wing it, and delete the LowerFilters setting, and after a reboot, the drive is usable again!