What is the difference between upgrading installation and customization when installing Windows 7

Upgrade installation: refers to retaining the application under the original operating system to upgrade the operating system. During the upgrade process, it will be installed according to the upgrade mode in the original definition of the Microsoft Group. After the upgrade, the disk will not be formatted, except for the operating system. The previous files can be retained after the upgrade installation, but the application compatibility changes may make some of the programs you originally installed unavailable, and some files that are not in the Microsoft Group data migration mode will be upgraded. Was directly discarded by the win7 version of the operating system.
Custom installation: refers to the user can customize the installation of the operating system disk partition, whether it is installed online, etc., many of the upgrade settings need to be manually set, if you choose a custom installation, in the process of data migration The win7 version of the operating system user can perform data migration according to their own choices, and the original data of the installation disk may be lost during the installation process.
The two upgrade methods have their own advantages, but depending on the actual situation, but if the win7 users need to migrate more and more complicated data during the upgrade process, it is recommended to choose a custom upgrade mode. This will make it more convenient in the process of data migration.
This small series special reminder: Before installing windows7, it is best to check whether your computer hardware supports win7 system