Windows XP bad for DVD........

[Gandalf256]

I have noticed a problem with windows XP. For some reason, i now cannot play some of my DVDs, my LG DVD rom drives just cannot seem to read them. The DVDs are not scratched, and it is inconsistent in the discs it cannot read. i use a LG 8x drive with a combonation of geforce 2 MX (prophet) and realmagic Hollywood plus decoder. does anyone know of any fixes for this? ( microsofts updates dont fix it!) i will be grateful for any replies.