vista says "No Network Adapter Installed"

On my Amilo notebook I have installed Atheros network adapter for my speedtouch router. After startup Vista says cannot find network adapter and it is also not present in Device manager. After restart it finds it and everything is fine. Also have Realtek adapter installed which seems to be there all the time. Can I use that adapter or will it cause conflicts(how to?). Also if I put my computer to sleep it cuts off internet after 2 hours. I have checked router settings and they seem to be fine. There is only one setting I dont understand "lease time client" which is set to 1 day, I dont know if that makes a difference.

many thanks