A problem that caused my connection to go dead. (HELP!)

I keep getting THIS error everytime. Just about 30 minutes after connecting internet (or not connect, I don't know, but I always connect internet after I open my com.) that error appear.

If I click on "Don't send" or do anything to close it, my connection will go down. It's not only disconnecting the internet, but it's like the internet is DEAD! The connection icon is still there, but it's not moving at all. I can't even check the status, disconnect, or connect again. All I have to do is restarting, which is kinda annoying because it kept coming and coming.

So what I do right now is hide that error message, and hope that I don't accidently click it. But that's not all! Few minutes after I didn't click it, another message appear:

Same as the old one, if I click OK, my connection will fail, so I have to hide it again!

This problem is really annoying, and I'm hoping to get rid of the problem, but since I have no idea what caused this, I don't know how to fix it.

If you know how to fix this problem, it would be greatly appreciated.

Thanks in advance,

Nattawat