How not to lose Wifi after waking up from standby or sleep mode?

I cannot believe this, but after months of trying to fix this, it turns out that, for me, checking ON (enabled) the "Allow the computer to turn off this device to save power” worked.

Got this idea from Intel’s My WiFi Technology stops working after resuming from sleep or hibernate in Windows 7. My guess is that the driver expects to turn the network card back on after sleep or on a cold boot, and because the option is turned off, it toggles the "switch" from being already on to off. Maybe?

Anyway it works for me now, perfectly.

Apparently, disabling a Windows power saving option causes a family of Intel drivers to malfunction. I was able to solve this issue on two Intel network card-equipped Lenovo ThinkPads. So if your computer also relies on an Intel WiFi network card, I'd suggest you :

1. Go to the Windows Control Panel
2. Click on System
3. Select the Device Manager
4. Right-click on your Intel wireless device and choose Properties
5. In the tab Power Management, enable the option Allow the computer to turn off the device to save power.

This solved my problem. As I am not using an English version of Windows, let me know if you can't find those menus.

For me on an HP EliteBook Folio 9480m (Windows 7 x64 SP1 with an Intel Wifi chip), the solution was to switch "Allow the computer to turn off this device to save power" OFF, and then back ON. Unbelievable!

After much aggravation, and trying all the power management options, I discovered that windows was using more than one utility to manage the wireless adapter. After exiting the trendnet utility and disabling it from starting up in the system configuration utility, I restarted the computer to find the problem solved.

The clue that led me to this was having more than one wireless icon in the system tray. The one in green happened to be trendnet.

For those, like myself, whose issue persisted after trying the apparently popular solution enabling/disabling the Power Management option, consider this:

Do you happen to have LogMeIn Hamachi on your PC? The quickest fix I came upon so far was to disable it "Network Connections" once you get the internet issue. Internet connectivity automatically fixes itself, and Hamachi network will will re-enable itself automatically as well.

This works for me; otherwise I used to disable & re-enable my Wireless Network... which fixes the issue only temporarily.

There's likely a more permanent fix to avoid this problem altogether, but I don't have the smarts or time to figure it out.