How old is this printer? Do you have a driver CD that came with it?
Basically speaking, if your computer doesn't detect the printer just by simply connecting it to the computer and powering it on, you either have a faulty wire or a faulty printer.
If it's a simple matter of not having the correct driver available you can probably obtain the drivers from the manufacturer's website support section.
In any case, you need to provide more information about the issue you are having so we can assist you better