Vista SP2 and CD/DVD drive recognition

Hello,

Has anyone had problems with SP2 not 'seeing' DVD or CD drives? Neither my internal DVD drive or an external (USB-connected) drive show up in Windows explorer, and disks placed in them won't play or install. The only thing I can think of is that I recently installed Vista SP2. Before I roll back, has anyone seen this issue? I've seen postings on issues with sound, but none where SP2 has made the entire disk vanish.