weird connexion problem

ok it's not really the first time it happen and the 2 other time this problem happen, every got back as normal on his own...

I doN,t really know how to explain but it seem that my "main" computer is not accepting my connexion.

ok i'll try to explain more in detail. I was surfing on the net, watching some video and then one video doesn't want to load, I think it might be a server thing because my modem show my that my connexion is working properly so it's not a "breakdown", but then I realize that any page or anything I try to load, is not working and my msn just disconnect, so in all this truly look that it's my connexion that is not working...

but as you see i'm now on my second computer that get his internet connexion by a wi-fi router and everything is working find here and I tried with my psp and same all green...so that's my computer that don't want to let me go on the net >.>

the other time it happen, I let it go for like some hour (one time a whole night) and it came back on his own, but now I don't know I have the feeling this problem will stay ar repeat itself in the future.

so I don't know maybe I have to reset my connexion or ip on that computer or something... anyone have a clue of what may cause this?

edit: I check something and when I enter cmd in execut and do a ipconfig, on this computer I can see my normal ip adress and all but on the other comp I don,t see the DNS thing and the ip adress is not the same it wasn't like that before and really don't know how to repair this...

Jam it back in, in the dark.