I have an Acer 7540 laptop, I have a WLAN Atheros b/g/n mini card installed. I wanted to change it to a Sierra Wireless MC5720 WWAN device. I installed it on my laptop and the Device manager could not find the device. Now I tried the MC5720 on another laptop so I know its not "dead" . Windows 7 has the drivers for the device already but when I install them I get a BSOD for the driver file of the device. I do have a Sierra wireless 598U installed that uses the same driver file for the MC5720 but I never had the 2 devices installed at the same time. Any suggestions?