Problem with wireless adapter, wireless network disconnects abruptly

Mine is Dell Inspiron 3537, Os: Windows 7 Ultimate x64. My laptop wifi works fine for some period of time, but suddenly the current wireless connection gets disconnected and no wireless networks appear in the list. The network connection icon in taskbar changes to no network connection (small monitor with yellow exclamation icon). The wireless adapter is still enabled only.
Well i found a way to bring back the connection and to show the available wireless networks by disabling and enabling the dell wireless adapter under "change adapter settings" in Network and sharing center. But this problem keeps repeating at unpredictable intervals and i have to disable and enable the wireless adapter everytime!. Please help me with a solution.
I have already tried the following,
1. Re-installing,updating wireless network drivers.
2. Re-installing entire OS with full format of all hard drives.
3. Disabled (unchecked) "allow computer to turn off this device to save power" option under power management tab of dell wireless adapter properties.
4. Changed the power saving options for wireless adapter to "maximise perfomance" for both on battery and plugged in modes.
Having tried all these still no luck, the problem persists. I borrowed a digisol wireless USB adapter from my friend. this works fine all the time with no issues. 
I have no idea why mine is not working properly. please do help.