Hello all.
I just got a new Z570 a couple days ago and have had a heck of a time getting the wifi to work.
Initially, I thought I wouldn't be able to connect to any wifi networks because my system just refused to connect to ANYTHING wirelessly except, curiously, my phone if I set it up for wireless tethering... I also ending discovering that I was able to my home wireless if I was withing a few feet of the router.
So, after suspecting I had a configuration issue preventing me from connecting to wifi networks at any real range and spending almost all of 2 days messing with configurations, driver updates, strange BIOS settings, I had just about given up.
Before calling for assistance, I figured I'd look at my wireless card and just check that it wasn't loose or anything.
And what would you know? It was. Specifically, the black power wire running to the wireless card was almost completely off. With the slightest touch, it just popped right off the card. So, I popped it back on to the card - snugly this time! - and restarted the machine. Now the wireless connects sure and strong!
What a hassle all because of a loose connection! Sheesh. I absolutely LOVE this laptop for features and build quality, but c'mon guys, let's try to get simple things like all of the wires connected before shipping these things out! 
So - TLDR version - if you are having wireless issues, shutdown/unplug your system, open the wifi access panel underneath and check that all the connections are tight. Mine weren't and it caused me days of headache but now it's working fine.
Hope that helps some of ya!
