How do i fix my computer's CD and DVD drives?

I have a Dell Dimension 8400 running on Windows Xp, we were running out of room and installed a terabyte hard drive and an extra gigabyte of ram. There were two fully functional disk drives before, now only one is registered. When you right click the driver's icon and select eject it states that "An error was encountered trying to eject 'Removable Disk (F:)'". But drives are able to open if you push the eject button in front and have power, however the disks aren't read and the computer doesn't recognize their presence.