win 7 security 2012 removal

Well for the second time in a month, we have a computer infected with Win 7 Security 2012.  I was able to remove it from the desktop with MalawareBytes useing the instructions here: http://www.bleepingcomputer.com/virus-removal/remove-win-7-security-2012 , but somewhere in the process windows lost the ability to recognize the internet adapter and after running down the options with both our ISP and the motherboard manufacturer, we had to reinstall windows anyway.

 

Now my son's laptop is infected.  Does anyone have any advice on the safest way to procede?  Would Norton Power Eraser be even more potentially problematic?  Or should I just do the same method as before and hope for the best?  Thanks for any help,

kate