Windows 7 installed on the first disk. Then I install 7 on a second disk. Then I format the disk 1. Does not start even more the second disc with the message at startup "insert boot device except etc.". how can I restore the start of the OS on the second disk?
You have to grab windows installer dvd/usb and issue a few commands in command prompt. Look here for details: http://www.howtogeek.com/howto/32523/how-to-manually-repair-windows-7-boot-loader-problems/