Back in 2005, it was already old. Yes, FSX still looks stunning with decent Addons (I also hav REX, PMDG, Airports).
But theres just 1 simple thing we hav to accept: the code could be way better, especially the scheduler.
Accepting this is hard, but hes right in some way. the engine is....well no comment.
I think Phil Taylor did some remarkable work to improve this, but from the beginning on, this simulator was simply no good from a technical pov.
Hi, did you check your DVD-Drive? As far as I know, XP uses DL-DVDs. These are not easy to read, especially on older drives. It might also need to be cleaned... Im pretty sure it is your drive.