1. Download Windows 7 USB/DVD
http://www.microsoftstore.com/store/msusa/html/pbPage.Help_Win7_usbdvd_dwnTool
2. Install the program and choose the iso file to put on USB external Key
3. Start PC with USB live
4. Choose Language to install and then:
5. Then choose "Repair your computer", NOT "Install now".
6. select "Troubleshoot" and then "Advanced options".
7. You'll find solve boot problem
8. Then you could use this command prompt option:
-bootrec /fixmbr
-bootrec /fixboot
