Win XP does not recognize DVD properly

I have installed windows xp on a 2.1mhz pc and I cannot get the DVD to function correctly. It doesn’t seem to recognize the installation of the disk right away. You have to wait for 1 minute before it recognizes that a disk has been inserted. I installed the new service pack 1 which at lest allows it to recognize a new disk is inserted but it still is extremely slow with poor performance. I changed DVD manufacturer but the same problem occurs.