I have a lite on 851s(8x Dual drive) i had been burning dvd's on memorex 4x dvd+rw but since i installed windows service pack 2 windows and bunrning programs tel me taht there isn't any media in the drive. I contacted lite on they told me to unsitalled the drive so it wentback to the old drivers at first it work but now i have the same problem and i did that again and it isn't working.
There is a known problem when "Suddenly a Windows XP machine is Unable to Find Your CD-ROM/DVD/CD-RW Drive". I know it happens with XP & XP SP-1, so it may also happen with SP-2. I have a page on my site that may be able to help you, if that is your problem.