win98 cd-rom drives

[Stern]

my friend asked me to get his external cd-rw working for him on his win98 setup. when i plug it in and install the drivers, and then restart, the external one is there as E:/, but the internal one (D:/) has disappeared and when i check device manager the secondary ide interface(sorry can't remember the exact name) has no drivers for it. so i install the drivers for it (windows finds them automatically), then restart, and the external one has disappeared, and in device manager it shows up as "USB Mass Storage Device" without drivers. When I install them, and restart, I'm back to the start again. Is there any way to have BOTH working at the same time somehow? Sorry I don't have more info on the comp.