hi i need saome help.

my cd/dvd drive is not working. i just bought a cd/dvd re-writer to add to my pc, but now the original cd/dvd drive is not being recognised.
i have gone into device manager, it is showing in'disk drives' instead of 'cd-rom/dvd drives'. device manager also says the drive is working properly (but it clearly aint)
in 'my computer' only the newer drive is recognised.
i have tried searching for a driver for the first cd/dvd drive i had (sony ddu1615-ds) but i cant find anything.

i am not techincally savy so please be gentle and patient with me.
what have i done wrong? please help.