I know it might sound silly, but are you 100% sure you've put the right wifi password in? Try doing it again, just in case.
Do you have an ethernet cable anywhere? If you do, try doing a wired connection just to see if it works that way.
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It says:
If you're connected to a hotspot or domain network, contact the network administrator.
Otherwise:
1. Unplug or turn of the device
2. Once all of the lights on the device are off, wait at least 10 seconds
3. Turn the device back on or plug it back into the power outlet
To restart a router or access point that has a built-in battery, press and quickly release the Reset button.
I guess you're using Windows 8/8.1? If so then there's your problem.
Lots of problems with drivers and Windows 8/8.1, especially/particularly on Intel wireless cards.
I've spent the last two months going back and forth with various manufacturers over why the wireless on a brand new laptop was experiencing the exact same issue detailed in the OP, even had the wireless card replaced under warranty, and every single time I've been told the problem lies with the drivers simply not working with Windows 8. This is the newest Asus and Intel hardware we're talking about here too, not some prehistoric device without drivers for Windows 8.
That's pretty strange and worrying for anyone who might not be entirely good with computers :/ But as @mrwoooooooo said that seems more of an issue with Intel and ASUS than with Windows 8, unless Windows 8 is asking the drivers to do something completely different for some weird reason :/ It does seem weird if the technology is roughly the same but Windows 8 refuses to acknowledge it. I wouldn't like to say who is at fault.