Shoutbox

I got an annoying problem with my Internet connection lately.

If I leave my computer idle for a long time (around 6 hours), the connection seems to be lost.
The LAN icon in systray says that my computer is still online.
It is still connected, but if I open my browser, the page won't show up.
It gives me page-not-found error, just like when you try to open a page without Internet connection.
I tried with different browsers, and I got same result, so I ruled out the browser as the culprit.

The same thing happens with my messenger.
I am still online, but no one can receive my message although I don't get message-not-sent error.
I don't know about people who try to send a message.
If I sign out and re-sign in, I can't be online because there's no connection.

I tested my connection with open video stream, and it could be on (meaning it showed the stream) although I leave my computer overnight.

Simply re-connect to the ISP doesn't work.

The only way to get my connection back is by restarting the computer...
or reformat my computer, which something impossible to do for now.

By the way, my internet connection is on cable.

Does anyone know how to solve my problem?

Thanks

Edit: If I do repair on the Internet connection, it goes through all stages, and it is okay.