"can't" is not a useful problem description. It does not say what you did. It does not say what happened when you did it. As usual, showing actual actions (commands) with their actual results (error messages, LED indicators, ...) can be more helpful than vague descriptions or interpretations.
> 1x Laptop WiFi can't connect (msg: NETGEAR05 No internet secured)
With my weak psychic powers, I can't see how you configured your (unspecified) router, or to what you connected it. Has it a model number? Look for "Model" on the product label.
> Is there a router limit of 4 connections?
No. Do your wireless devices all use the same radio band?
Visit http://netgear.com/support , put in your (actual) model number, and look for Documentation. Get the User Manual (at least). Read. Beyond the basic set-up instructions, look for the LED descriptions and "Troubleshoot".
