How to restore previous Windows installation after Windows 7 upgrade

If you upgraded your Windows Vista or Windows XP computer to Windows 7 using the upgrade option, you still have your old files on your disk in a folder called Windows.old. It’s possible to revert back to the earlier operating system using this folder - this is why that folder exist. The following article will show you how.

Step 1: Determine whether there is a Windows.old folder and whether there is sufficient free space on the Windows hard disk

1. Click Start, and then click Computer.
2. On the View menu, click Details.
3. In the Free Space column, note how much space is available for Local Disk (C:) under the Hard Disk Drives area.
4. In the Hard Disk Drives area, double-click Local Disk (C:), and then determine whether the Windows.old folder exists. If the Windows.old folder does not exist, you cannot restore the previous Windows installation to this computer. You must backup and restore or transfer your files to the previous operating system.
5. Right-click the Windows.old folder.
6. Windows 7 will determine the size of the folder after several seconds.

Determine whether the Windows.old folder is smaller than the free space that is available for Local Disk (C:) in step 1.2.

Note If the Windows.old folder is two times as large as the free space that is available for the Local Disk (C:) entry, you may be unable to restore the previous Windows installation.

Step 2: Start the Windows Recovery Environment

1. Put the Windows 7 installation disc in the DVD drive, and then restart the computer.
2. Press a key when you are prompted to restart from the disc.
3. In the Install Windows window, select a language, a time, a currency, a keyboard input method or other input method, and then click Next.
4. In the Install Windows window, click Repair your computer.
5. In the System Recovery Options window, click the version of the Windows 7 operating system that you want to repair, and then click Next.
6. In the System Recovery Options window, click Command Prompt.

The Command Prompt window opens, and it displays the command prompt. The command prompt is where you will type the commands that are described in the following steps.

Step 3: Move the Windows 7 folders to a new Win7 folder

Note When you type one or more of the commands at the command prompt in the following steps and press ENTER, you may receive the following message:

“The system cannot find the file specified.”

If you receive this message, go to the next step in this section, and then type the command in that next step.

Type the following commands and press ENTER after each command:

C:

Md Win7

Move Windows Win7\Windows

Move "Program Files" "Win7\Program Files"

Move Users Win7\Users

Attrib –h –s –r ProgramData

Move ProgramData Win7\ProgramData

Rd "Documents and Settings"

Step 4: Copy the contents or move the contents of the Windows.old folder

Note When you type one or more of the commands at the command prompt in the following steps and press ENTER, you may receive the following message:The system cannot find the file specified.

The system cannot find the file specified.

If you receive this message, go to the next step in this section, and then type the command in the next step.

Type the following commands and press ENTER after each command:
move /y c:\Windows.old\Windows c:\

move /y "c:\Windows.old\Program Files" c:\

move /y c:\Windows.old\ProgramData c:\

move /y c:\Windows.old\Users c:\

move /y "c:\Windows.old\Documents and Settings" c:\

Step 5: Restore the boot sector for the previous Windows installation

Type one of the following commands at the command prompt, as appropriate for your situation.

Note In the following commands, D: represents the DVD drive. If the DVD drive on the computer is represented by a different letter, such as E:, use that letter in the command.

When the previous Windows installation was Windows Server 2003, Windows XP, or Microsoft Windows 2000

Type the following command, and then press ENTER:
D:\boot\bootsect /nt52 c:

When the previous Windows installation was Windows Vista

Type the following command, and then press ENTER:
D:\boot\bootsect /nt60 c:

Step 6: Restore the Boot.ini file for the previous Windows installation of Windows XP or of Windows 2000

Note Follow these steps only when the previous installation is Windows XP or Windows 2000.

Type the following commands and press ENTER after each command:
Attrib –h –s –r boot.ini.saved

Copy boot.ini.saved boot.ini

Step 7: Close the Command Prompt window, and then click Restart

Type the following command at the command prompt, and then press ENTER:

exit

Click Restart to restart your computer.

[via Microsoft Support]