Interesting Internet Issue

History:
I'm currently in Korea and Koreans have quite a few differences in the infrastructure of the internet which makes the entire country use Windows XP only. This deals with security protocol as I remember reading an article, anyways, I doubt that that has anything to do with my problem.

My problem:
When my computer (Vista 32) sits idle on the internet for a period of time, the internet stops working until i restart the computer or re-log into the computer.

Setup:
This could be a simple fix because I have disabled a few services, many are on manual however. When I was in America I always connected to the internet through a network, now i'm connected directly via a modem.

The problem is annoying and any insight as to why it happens or what can be done about it would be much appriciated.

Much obliged, Kenny.

Have you tried upgrading your device drivers?

I went and checked out the network settings and the person who installed the internet here did do a good job. He made several errors and I actually had two LAN's that did the same thing and they seemed to be conflicting when the computer was idle.

I just deleted the networks and changed a few settings and it seems to be working now.

Device drivers were up to date. Thanks for the advice though.