I have Windows 7 Ultimate 32bit installed on a Dell Latitude XT Tablet and for the life of me I can't figure out this really weird problem.
The symptom is that the Wireless will disconnect from the AP and if I tell it to scan again, it says there are no APs in the area. I do have another wireless card in the laptop and if I disable the first one and enable the second, I am able to get onto the wireless however if I want to use the first card again I have to restart. I tried enabling/disabling the device, nothing will kick start the wireless again in the first card without a restart. I even tried different drivers. So, it seems it is random but it does occur more often when there is increased network activity (ie downloading a large file). The laptop doesn't seem to be overheating.
I have tried the following: Under "Change Advanced Power Settings" for the current power profile, I set the "Wireless Adapter settings" to "Maximum Performance". Under device manger, I went to the card in question, and went to the advanced tab and set the "Power Saving mode" to "MAX_PSP"
Both cards I have seem to exhibit the behavior after awhile. Both models of those cards are:
Dell Wireless 1505 Draft 802.11n WLAN Mini-Card
Gigabyte GN-WS30N 802.11n mini WLAN Card
Has anyone have any ideas or ran into this before?