My boss asked me to fix a problem on his laptop where he has a good wireless signal, but for some reason it had recently been not connecting to the net.
Tried system restore...nothing.
Laptop is Vista by the way. Firewall's not blocking the net.
Thanks in advance.

Remove and reinstall the Wireless software, then check your connection security codes carefully... download the latest version of the setup software from the manufacturer.
There are really too many options for us to give a simple explanation in the space available.
Wireless is one of those tricky ones. Once you fully understand it on a given machine, it is very simple. But until you understand it, the frustration level is extremely high... So do your home work with a lot of reading of materials related to that laptop and to the software and connection that he has installed. It can be a quick fix, but usually is not.

but the wireless system came standard with the laptop

Is this within his own network? Or with wireless signals out in the 'real world'? This happens to me a lot with my home network. The only thing i can suggest is to reset the router and start from scratch. He will need to have a wired connection to the router in order to do this.