Installation failure due to/dev/root does not exits in centos 7

This is what I wrote.CentOS-7.0-1406-x86_64-DVD.iso, Downloaded from the 163 image, and then started the disk with a USB flash drive made by ultraiso 9.6. However, this error was reported during installation and I searched it for a long time. I tried the following method, it is correct and feasible. at last I will explain the reason

Step 1:

After the preparation is complete, change the label name of the USB flash drive to whatever you want, but it is better to be simpler, because it will be used later.

Step 2:

Start installation. On the installation page, select the first option, that is, install centos 7, and press e to edit the startup Item, run centos 7 x86_64... change the string

You can change the string and press Ctrl + X to start

Cause: the length of the label in win7 is not long enough, so the hard disk cannot be found during installation.