Installation Type Facts
There are three Windows 7 installation methods:
||A clean (also known as custom) installation is performed on an existing or new PC and installs Windows 7 with fresh settings. Choose a clean installation of Windows 7 in one of the following cases:
When performing a clean installation on a computer which already has a previous version of Windows,
- There is no operating system yet installed on the computer.
- The installed operating system does not support an upgrade installation to Windows 7.
- The computer has more than one partition and needs to support dual-boot or multiple-boot configurations.
- You prefer a clean installation.
- You should perform a backup of the existing system.
- You can use the backup to restore user data to the new installation.
- If you are unable to complete the installation, you can use the backup to restore your existing system.
- Windows 7 creates the C:\Windows.old\directory and retains system and user files from your previous operating system in the directory.
- Files in the system-created directories are placed inside the Windows.old directory. These directories include:
- Documents and Settings (Windows XP) and Users (Windows Vista)
- Program Files
- Files and folders outside of the system-created directories are not touched (unless you repartition or reformat the hard disk during installation).
- You can install Windows 7 onto a different partition or hard disk to keep an existing operating system installation (such as Windows XP) and user data. Use this option to create a dual-boot system, or to access your existing user files when booting into Windows 7.
Be aware of the following when creating a dual-boot system:
- Windows 7 must be installed on a partition that uses NTFS. Windows 7 can read a FAT16 or FAT32 partition, but cannot be installed on one.
- When installing different versions of Windows on the same system, install the oldest version first, and install Windows 7 last.
- Programs and drivers must be installed on each operating system.
- To boot from a specific installation on the dual-boot system, use BCDEdit to modify the default Boot Configuration Data (BCD) boot entry.
||An upgrade (also known as in-place) installs Windows 7 on the same partition as the existing operating system, but maintains applications, user settings, and user files. Be aware of the following:
- You can upgrade from Windows Vista service pack 1; you cannot perform an upgrade installation from Windows XP.
- A Windows 7 upgrade automatically rolls back to Windows Vista if there is a failure during the installation process.
- You can also roll back to Windows Vista if you have not performed a successful log on. If you want to return to Windows Vista once you successfully log on to Windows 7, you must perform a clean Windows Vista installation or restore the system from a backup.
||A migrationcopies user files and settings from an existing computer to a new Windows 7 installation. Use a migration when you would like to upgrade to Windows 7 but an upgrade is not supported, or if you want to perform a clean install but retain your current user settings and data. To perform a migration:
- Save existing user settings and data to a temporary location.
- Install Windows 7 on the same computer (over the existing operating system) or a new computer. For example, you might perform a migration on an existing computer that cannot be upgraded to Windows 7, or on an existing computer if you just want to start with fresh operating system settings.
- Transfer user settings to the new installation.