I always lose connection when it goes into sleep, hibernation mode or if I lock my laptop and log in at a later time. I think it's also started dropping when I'm afk or idling. My network gets a limited connect message and if I disconnect and try to reconnect, I get a message saying that Windows can't detect any networks. Disabling and then enabling the wireless network adapter doesn't work as at this point, trying to re-enable the adapter doesn't work. Checking the adapter under the Device Manager shows that "the device cannot start". I've also tried uninstalling and installing the driver for the network adapter, restarting my router, disabling my firewall, disabling the power settings on the adapter, almost everything I've read about on this issue and so far hasn't had a lasting effect.
My laptop is an Acer Aspire 7551-2575 and it has a Broadcom 802.11n Network Adaptor if it helps.
Edit: I've just stumbled across a new trick. Before going into sleep/hibernation/etc., turn off your wireless. For me that's pressing FN+F3. Then when you log back in, turn it back on!
Edited by redqueenie, 20 October 2010 - 10:44 AM.