Why is Ubuntu 14.10 not installing?

Question

Installer

I installed Ubuntu 14.10 from LiveCD on MSI B75SA with Windows 7 x64. Instructed to put next.
The process has reached the end, - I clicked "restart".
The computer didn't restart, it just hung.
Now, when you turn it on, it immediately boots into Windows 7 as before.
Msconfig shows, as before, only one boot option.
On one of the external USB HDDs, 2 new ext4 partitions of about 15 gb each appeared. They were created by the installer.
How do I dual-boot when I turn on my computer, and in general, just boot into UBUNTU first ?

Answer 1

Boot from livecd and restore grub

Answer 2

so you put on the same screw as 7 or still on the external screw?