I have the stock phone. I forced it to see the network by going to Settings, Wireless & Networks, More, Mobile Networks, Network operators. This will force a scan to see what networks are available. Pick AT&T (assuming that who your provider), and it should turn on the Cell Service.
If it does not work, try going to an AT&T owned store and ask for a new Sim Card. (That is what I had to do.) They put it in with no questions, except for marveling at my wonderful SGN. No plan or feature changes happened.
For the Wifi, that is different. Go to Settings, Wireless & Networks, Wifi (and turn it on). You can re-scan for networks anytime. I had 11 networks in range, so it took some looking to find mine. You may need to re-enter the security settings several times to get it right. (Delete old settings by using "forget" below the network you select.) Once it works, it should keep on working with no further adjustments, at least mine does that.
When signals are seen, the grey icons will show blue as a signal strength. (I'm not sure they are accurate.)
Palm IIIxe --> Palm LifeDrive --> Tilt --> Samsung Galaxy Nexus (Here Now!)