|Go into setup..bios and see if it is recognized.|
If not then check connections (power and ribbon cables).
Then check the jumper on the cdrom. Compare new one to old one.
Master/slave or cs?
Being that the system has a few years on it you should also check to make sure it has the right driver. Start/control panel/system/hardware/devise.
From what you have said "my dvd player
stopped working so I replaced it with a new one ", I have a feeling it's a bad ribbon cable or something other than a doa dvd.