network connection to router needs reset

I am constantly needing to reset the network adpater in order to connect to my router/internet. This is one of those niggly problems that occurs quite often but not always...

I have checked driver updates and all OK. Any suggestions welcome.

Thanks.

Adapter: Intel(R) 82566DC-2 Gigabit Network Connection
Router: Netgear N Series (had the same problem with Belkin 54g)
OS: Windows Vista Home Premium 64 bit

Same problem occurred again. This time it took 3 attempts to 'reset the adapter' and 'get new IP address' after right-clicking diagnose and repair. Really puzzled.... Does anyone have any ideas?