Re: tablet wont connect to wifi
If none of that helps, is anything else (laptop, another phone) able to connect to your router by wifi? If yes, it's not a problem with the router. It's entirely possible (though rare) that the wifi radio in the phone failed.
If no, it's possible that the router failed. Call your internet provider for assistance. (Routers do fail, but good ones - Linksys, D-Link - last so long that sometimes you wish they'd fail so you had a good excuse to buy a newer one with more features.)