Might be a problem with one or more network adapters

I have a Dell Inspiron running Vista Home Premium 32bit. I am connected directly from my modem to my laptop. About a two weeks ago, I started having connectivity problems with my VPN. I have checked my device manager and all network drivers are running fine. But I keep having connection problems with my VPN. It will connect for 15-20 minutes and then I lose the connection. When I try to reconnect I get this error message: "You might have a problem with one or more network adapters".

Please help!!!