Somethings wrong with my network card/internet

[Siphon]

On one of my computers the internet does not get through sometimes. The other computers connected to the same router get internet. This is my newest computer and it is the one in my comment. In the device manager it says the network adapter is working properly and the router even detects it, but no activity reaches the computer. I have tried switching the wire, but it didn't work. What can be the problem?

I use the gigabit lan built in on the motherboard, not an actual network card.

 

[Siphon]

i fixed it, i ended up unplugging the computer for 5 minutes and that must have restarted the network card.

However, I still think that my network card was locked up for some reason, maybe software. Any ideas? (maybe virusscan or micrsoft anti-spyware?)