How to deal with Win10 system installation error problem

After the launch of the Windows 10 preview, many people rushed to adopt the early adopters. However, some people failed to install. He couldn't understand why others could install it, but he couldn't. This article brings the requirements and conditions for installing Win10, I hope to help everyone.
--Please download and install this preview only when the following conditions are met
• I hope to try out the software that is still under development and I would like to share my views and opinions about the software.
• Know how to back up your computer, format your hard drive, and install the operating system from scratch.
• Learn how to restore your previous operating system (if necessary).
• Really understand the computer, you can easily solve the computer problem.
• Don't mind having a lot of updates or major changes to the UI design after a while.
• Do not install this software on a computer that you use every day.
--System Requirements
Basically, if your computer can run win8.1, you can safely start the installation. If you are not sure, don't worry about — Windows will check your system to make sure you can install Win10 Technology Preview.
• Processor: 1 gigahertz (GHz) or faster
• Memory: 1 GB (32 bit) or 2 GB (64 bit)
• Available hard disk space: 16 GB
• Graphics Card: Microsoft DirectX 9 Graphics Device with WDDM Driver
• Microsoft Account and Internet Access
There is no love for no reason in the world, nor hate for no reason. This shows that there is a cause. The equipment and conditions of each computer are different. If you check in, can you find the reason for the installation failure?