Malfunctioning networkcard?

I'm not sure if this is the correct section to post this, but as it seems to be connected to the network somehow, this seems like the best place.

For a few days now, my computer have refused to shot down properly, it hangs on the "Shutting down" screen, and I have to manually turn it off. I tried everything, from running virus programs to uninstalling the programs I installed the day the problems started, but nothing helped until I disabled my network card before I shut down my computer. Then it shut down like normal.

Is this a sign I should buy a new network card, or may there be something else wrong?
The computer is just a few weeks old, so it would be weird if the network card would be malfunctioning already.

Hoping someone can help me,
Chris