Sometimes the PC is under the desk or whatever and you don't want to keep leaning over to press the eject button or push the drawer in, so a batch util to open & shut the drawer can be handy.
However we have had queries from infantile schoolboy pranksters who think it is funny to open and shut classmates or teacher's CD tray, hence my suspicion. Sorry if i was wrong...
if you have Nero installed you have Nerocmd.exe which is a command line utility
If your cd drive letter was X: then these commands would do what they suggest
nerocmd --eject --drivename x
nerocmd --load --drivename x
You have to either have nerocmd.exe on your PATH or else include the full path to nerocmd.exe