Installing Ubuntu onto several XP Pro machines. Successfully installed on several. 5 remaining do not recognize Sony DVD+RW 4.7GB disk at all. I burned ISO image using DVDFab (forgot exact name). Done all kinds of things (updates, master/slave swaps, IMAP service, & million others). Also, swapped a DVDs Rom from the machines to non-working (ones that can not recongnize) ones, no luck. Disc is not being recognized at the boot either, while other boot discs are. It appears 99% Windows OS problem. Do you think it is related to "magic Windows problem with 4G discs"? - read somewhere but could not follow the thread. That's the only thing I have yet to try. I also can acros a post that this may be built-in to one of the Windows patches as a protection against illegal (movie, software & etc) distributions. If you think you can not post the answer I can try to addess my installation problem, please do personal messaging