ipad 3 os 6 will not log into wireless network,even though its used it many times .When i try to reset network in general preferences it ask for a password but I've not set one can you exsplaine this.Its not the wireless point thats not working all my ok?

Easiest thing start with is a reboot of the iPad - hold both the power and home buttons until the apple logo appears and it restarts, ignoring the red slider if it appears.

If that does not help, work through the troubleshooting guide at http://support.apple.com/kb/TS1398. When you do those steps, the step of powering down the router, you need to disconnect the power to be sure it is not in standby mode.