Loss of connection, then no Wi-Fi networks listed

I've been having this problem every few hours or so. I get disconnected from my home wireless network, and when I check the list of networks it isn't there anymore. I try refreshing the list of networks a few times and eventually there are no networks to be found (wireless connection tray icon has a red X on it). I've tried resetting the wireless adapter by going to Network Connections but that doesn't help. I've run the troubleshooter but that doesn't help either. The only temporary fix I've come up with is either sleep and wake up or restart the computer, but I'll get disconnected again after an hour or so.

Can someone please help me get rid of this problem for good?

(Running Windows 7)