If you have tried a complete reboot of the Transfromer Prime, here is what I wrote in another thread that may help. Could be that a neighbor changed ISP, routers, etc.
Here is what I wrote:
First let me say that I work in the IT industry and fix/correct WiFi issues all the time. When dealing with wifi routers, all the manufacturers set the routers channel to auto. One would think that it would mean scanning for a free channel. It DOESN'T!
The 3 default channel's that routers use are channel 1, 6, & 11. As another poster said, grab WiFi Analyzer from the market and scan for used channels and force the router to an unused channel. Your wifi will stop competing for signal strength with near by routers.
I use this app on my phone all the time in small businesses when having wifi issues.
Now on my Transformer Prime, the wifi reception is a little weaker than some of my other devices. But so far, has not caused any real issues when the wifi is setup correctly.
David