Codes:

stpe 1:type
bootrec /fixmbr

step 2:
bootrec /fixboot

step 3:
bootrec /RebuildBcd

after thet press
Y

eg Screenshot:
http://2.bp.blogspot.com/-JBSQNxxX5fI/UYUlNAzybQI/AAAAAAAAAvo/hH5pAaUAkZY/s1600/drv_unlock3.JPG