Missing drivers for ethernet controller

Hi,

For some reason my laptop is missing drivers for ethernet controller. I've had the laptop for about 5 years, and never fiddled with the ethernet drivers or anything, but noticed this when I went to another house and attempted to connect to their internet (and was unable to find their wireless). Bizarrely, it seems to work intermittently for short periods, and then I lose connectivity and have to restart the computer.

I've got a Dell Inspiron 1545. Running Vista.

If I search automatically to find driver software to update, I don't have any joy. Could anyone please advise what the most appropriate driver would be and where I can find it?

Many thanks,

Chris