Whew ... I've never heard that one before. First of all, compatibility mode is for software that's already been installed (for running it). It looks like you've got some sorta other problem lurking if your computer can't read your cd-rom drive. Is it all cdroms it can't read or only older ones or ...

ya i also agry with u r remarks but i want to say that if all the capability of xp is fine then why it is not possible to register online,and if a xp orginal cd is one time installed and registered then is it possible to reinstall xp with that same xp cd on that same system if some problem occeared to that system?