Lenovo PCs installed custom software even if you wiped them
 

Samsung isn't the only Windows PC maker to have hijacked Windows' update process as of late. Users have noticed that some Lenovo PCs running Windows 7 and 8 (such as the Yoga 3) had firmware that automatically downloaded and installed Lenovo's own...

http://www.engadget.com/2015/08/12/l...cid%3Drss_semi