Setup /p f Works Only in Windows 95 (271771)

SUMMARY

When you use the setup /p f switch in Microsoft Windows 95 it may enable a clean registry mode, forcing detection to delete the following registry key before starting:

HKEY_LOCAL_MACHINE\Enum\Root

In Windows 95, this switch is ignored when Setup is run from within Windows. In Microsoft Windows 98, Microsoft Windows 98 Second Edition, and Microsoft Windows Millennium Edition (Me), setup /p f is always ignored, even when Setup is run from MS-DOS.

MORE INFORMATION

The root subkey contains *PNPxxxx entries for legacy hardware that is not Plug and Play. This is only a small subset of the hardware information stored in the registry.

To troubleshoot device issues when other troubleshooting has failed and you are forced to reinstall, follow these steps:

Back up the registry.
Restart the computer in Safe Mode.
Remove all devices from Device Manager (including system devices).
Restart at a command prompt, and then run Setup to reinstall Windows.

For additional information about the HKLM\Enum registry key, click the article number below to view the article in the Microsoft Knowledge Base:

250530 Description of the Subkeys Contained in the HKEY_LOCAL_MACHINE\Enum Registry Key

For additional information about how to back up the registry, click the article numbers below to view the articles in the Microsoft Knowledge Base:

132332 How to Back Up the Registry

256419 How to Back Up the Registry in Windows 98

NOTE: Windows 95 runs detection before the first restart of Setup. When run from MS-DOS, Windows 95 Setup runs detection under mini-windows. Therefore, the /p f detection switch is processed. Because Windows 98 and later versions of Windows run detection after the first restart, detection always runs under a Windows environment, even when Setup is run from MS-DOS. Therefore, the /p f detection switch is always ignored in those versions of Windows.