Internet Problems?

[Nick]

My internet connection was fine until my internet got unplugged over night for about 6-8 hours. When i plugged it back in everything worked fine except my computer which is connected wirelessly. Windows said it was a dns problem so i flushed my dns and did every basic trick in the book (changing dns to googles ect) but now i can connect only by unplugging my routers power and unplugging my internet cord into my router than plugging the power back in then the internet. this works for about 3 hours until i have to do it again. How do i fix this permanently?