for some reason my dvd burner is not reading blank dvds anymore. It reads and burns to cds and reads pre-recorded dvds but when I put in a blank dvd it doesn't do anything. Worked fine a few weeks ago. I've had some pals install some freeware dvd stuff on in the interim but I've deleted it and still won't work. I have a hl-dt-st dvdrrw gca-4164b. It's properties say it's working fine. Can anyone help me as to what the problem is? thanks.