Android tablet will not connect

Greetings I first need to tell you the setup. I live in a 2 story house. Cable entry is downstairs. we bought a router to have 5 computers to log on the net. About a year later we acquired lap tops. So to have wireless I installed a wireless router on my desk top, which is upstairs. all was good. through the years down stairs router died. I have N300 Netgear upstairs. I bought another exact Netgear N300 both wireless and installed. all is good WP2 All you have to do was scan for providers and put in password and you was connected. There is a add on on this house and outside wall is 12 inches concrete. There is a desk top in that area. one of the five originals coming off dowstairs router. for wireless there We bought a Belkin router, It did not work until I brought down my win 8 Laptop accessed belkin router added update I obtained from belkin, Now access granted.

Now we have Android tablet in Belkin area, all was good until about a month, only a month old You can scan for providers and belkin shows with full signal, You put in password and shows hardly any signal and it flips in and out with acquiring connection. As this is going on a laptop right next to me is on the net on facebook. I brought it upstairs and it accessed router almost instantly a lot different then in that area. I reset tablet twice and still same downstairs in concrete area. I wonder If I have a bug in tablet? I almost forgot I have a dell tablet that I took to area and sitting next to accessing lap top I can also access with My Dell which is windows 8.