Use the command "lspci" to identify the chip used in the wireless card, find the right item on the resulting list, and use it to search the Internet for your next step.
If you already know what chip you have and have configured it, do you see that a driver module is being loaded? Use the command "lsmod" or "dmesg" to see what is being loaded for wireless function.
You haven't posted very much information, nor anything about what you've already tried in attempting to solve your problem.
Which edition of CentOS are you using and on what system?
Last edited by thorkelljarl; 11-08-2012 at 09:23 AM.