Hi Lorme and welcome to Android Forums!
My first question involves the speed of your router, the speed of your tablet and whether the router is backward compatible. My first n-speed router was n-speed only... and none of my g-speed devices would connect. I got another router that was compatible with all speeds, and everything connects.
Make sure that the two match up, and we'll continue from there. Hope this helps.
Great to have you aboard!