Laptop wireless card issue driving me crazy

[Suhas]

I have a Dell Studio laptop(Studio 1558) with a DW1520 Wireless N WLAN half mini card(Broadcom) that is intermittently switching off wireless on start-up under Windows 7. If a connection is made at start-up it works fine however every one in three start-ups fails to initiate wireless (I see a red cross over the wireless bars in the system tray). To date I have tried the following however none of these solve the problem.

1. FN + F2. Nothing happens
2. Launching the Dell Windows Mobility Centre by pressing [Windows Key + x] to switch the wireless hardware radio on and off .
3. Unchecked "allow the computer to turn off this device to save power" under power management
4. Restarting the WLansvc service

I have also installed the latest Dell Wireless WLAN 1520 Half MiniCard Driver (Version: 5.30.21.0, A01, Release Date: 10/7/2009) from the Dell Support Site.
The laptop has Win7 Professional 64-bit version.

At present my only solution is to repeat restarting the laptop until I regain a wireless network connection. I am also hearing a faint distorted playback of the start-up windows tune on start-up when wireless start-up fails and was wondering whether this is indicative of a hardware fault with my wireless card however this may be a red herring!

I did notice that whenever it fails either the wireless device does not show up in Device manager at all and sometimes shows up with an error symbol indicated. When I saw in properties for the error message it showed "This device cannot find enough free resources that it can use. (Code 12)
If you want to use this device, you will need to disable one of the other devices on this system."

Is there any easy way to determine whether this is a hardware fault or software configuration with my network card? The problem is intermittent and does not happen on every startup which is confusing. Any suggestions or ideas would be appreciated.