Iphone 5s can't connect to Wi-Fi at all?

My phone doesn't connect to any Wi-Fi either. Just tried to connect to the Wi-Fi at work and didn't work. My friends suggest me change to use Cisco router. Does someone who had used cisco products?
http://www.router-switch.com/

On your iPhone, go to Settings > General > Reset > Reset Network Settings.
Restart your iPhone by holding down on the Sleep/Wake button, then slide to power off.
Hold on the Sleep/Wake button again to turn your iPhone back on.
Then, try to connect to your Wi-Fi network again.

If the issue persists, seek this article by Apple for more help: http://support.apple.com/...398?viewl…