For updated firmware, check out your PC manufacturer's support site. If a firmware update doesn't work, it sounds like the drive may be on its way out. How old is it? What kind of use has it been through, i.e. do you do a lot of DVD burning, etc...?
If it stopped reading and writing of a certain media type, the laser is probably bad and you need to replace the unit. New DVD burners are $20. I have had drives go out after not too much use, and others like my 2x dvd burner that are still going strong after 1000's of burns.