EXACTLY what do you do in the "Control Panel" when you "turn it back on"?
If external, have you swapped in a known "good" card to verify whether it's the card or the circuitry?
If Internal on the motherboard, have you tried finding and installing an updated driver? Updated drivers are being released frequently because of Vista's conflicts.
If you're connecting to a DSL or cable modem, make sure to updated the firmware on your modem or router.. It's another issue of Vista..
Hope this helps.
My 3050 acer aspire laptop's ethernet adaptor keeps shutting down.I have to go into the control panel to turn it back on to get online.The lap top has 1 gb of ram,1.8 ghz sempron 3500 cpu and an 80 gb hard drive.The laptop doesn't have too much to load when it boots.It runs vista home basic.I've had the laptop for 3 weeks.