Shouldi install super multi drive disc to my existing xp pro ,is it necessary , would it be good or harm my computer
You are referring to installing a new physical drive, correct ?
It won't harm your system. It will give some extra support that basic drives do not.
This means that the drive supports reading and writing to all types of DVD media.
Also supports the + standards as well. Most basic drives do not support all of these types. Check before you buy.