Try running the script as it is with a file in the same folder as the script called COMPUTERS.TXT

Inside that file you should have a list of computer names to use.

COMPUTER01
COMPUTER02
COMPUTER03
COMPUTER04
COMPUTER05


ETC....


Then when you see and get that going you would use the $Computer for the name of the computer name to run the NETDOM command against.

If you need further explanation or example let us know.