Windows 7 Access denied all of a sudden

[xbritxrochellex]

I was connected to the internet for about 45 minutes and then all of a sudden it stopped working. so i reconnected to it and this balloon message comes up and tells me additional log in information may be required and to open my browser to do so. (its never done this before) s so when i did i get this message

The other computers connected the this wireless network connect fine except for mine. and my computer works fine when i connect to other networks its just this one. what is happening? i'm confused. there is no error number. nothing.