I have windows 8 and when I got it it was working fine then one day it said their was unavailable wifi? Does someone know how

Reset your router,and modem. Reboot your laptop and try to reconnect to the wifi.

Uninstall and reinstall the wifi drivers. Look for a firmware upgrade for your router.

If the above does not work, make sure the wifi switch is turned on for the notebook.

Nest, go to a wifi usb adapter, which should bypass the hardware issue of the wifi in the notebook.
 


Yeah, you should almost always try to restart involved devices before asking for help as it can fix it more often then you would think, of course you can still ask afterwards!