So there are 4 partitions. One of the four has Windows 2000 on it now. You have now tried to install Nero, and opened it and it can't find the drive. So you probably have C,D,E,F drives as hard drives. G might be a cd rom drive.
Can you read cd's with the drives okay?
INSTRUCTIONS TO INSTALL NERO ON THE PARTITION WITH WIN 2K NOW ON
Is Nero installed on the partition (drive) that Win 2000 is installed on? This might be a problem if not, because it might not have set up the registry or something correctly since driver information will not be on a seperate drive, if these don't have windows on. If this is the case, simply install nero again on the right drive
If this isn't the case, you might have to install the cd rom/dvd drives since they aren't running. If they read discs though, ifgnore this and it might be the above option.
ONLY IF A DISC CANNOT BE READ INSTRUCTIONS
Go into System within Control Panel, and into HardWare, Device Manager.
Under DVD/CD rom drives in the list check that the drive is there, and doesn't have a cross or question mark next to it.
if it does, you will have to find the disc that came with the drive and run the Add Hardware wizard, again in Control Panel to see if it recogognises the hardware but it has not been installed yet.
Hope this helps (You'll have to get used to my long posts. I'm sure they are detailed enough though :P The caps are not to shout, but to suggest a title)