In tip 3920, I described performing an in-place upgrade of Windows 2000.
Microsoft Knowledge Base Article 315341 contains the following INTRODUCTION:
This article describes how to perform an in-place upgrade, or reinstallation, of Microsoft Windows XP. This is also named a repair installation. It reinstalls Windows XP to the same folder. You may want to perform an in-place upgrade if your installation of Windows XP must be repaired. Such a repair installation may be required if one of the following conditions is true:
|•||You cannot start Windows XP in Safe Mode.
For additional information about how to start your Windows XP-based computer in Safe Mode, click the following article number to view the article in the Microsoft Knowledge Base:
315222 A Description of the Safe Mode Boot Options in Windows XP
|•||The problem is caused by a recently installed Microsoft software update, and you cannot solve the problem in any other way.|
|•||There is a registry problem that cannot be solved by using other tools such as System Restore.|
|•||You must apply default (file and registry) permissions to your Windows XP installation.|
|•||You must register Component Object Model (COM) components and Windows File Protection (WFP) files.|
|•||You must use the Windows Setup program to enumerate Plug and Play devices again, including the hardware abstraction layer (HAL).|