Differences Between Windows XP SP1 and Windows XP SP1a
To determine if you are running Windows XP SP1, right-click My Computer, and then click Properties. If "Service Pack 1" appears under System, you are already running Windows XP SP1. There is no benefit to installing SP1a if you are already running Windows XP SP1. Microsoft does not recommend that you install SP1a if you are already running SP1.
Windows XP SP1a is the same as Windows XP SP1 except that the Microsoft virtual machine (VM) is removed in SP1a.
- Windows XP SP1a does not include or install the Microsoft VM, which provides support for running Java programs.
Note If you are running Windows XP or Windows XP SP1 with the Microsoft VM, you can continue to update the Microsoft VM by using Windows Update. If you are running Windows XP without the Microsoft VM, you do not have to install updates to the Microsoft VM. Therefore, these updates are not offered to you when you visit Windows Update. Microsoft is no longer able to provide a download of the Microsoft VM for computers that do not already have the Microsoft VM installed. For more information, visit the following Microsoft Web site:
- Click Start, and then click Run.
- Type cmd, and then click OK.
- At the command prompt, type jview and then press ENTER.
If you are not running the Microsoft VM, you receive the following error message:'jview' is not recognized as an internal or external command, operable program or batch file.
- When you install Windows XP SP1a, the following changes are made to the registry. These changes indicate that SP1a is installed:
- A string value is created in the following registry key and its value data is set to "a":HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SubVersionNumber
- The value data for the Descriptionstring value in the following registry key is updated to include "SP1a":HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP\SP1\Q324720
- A string value is created in the following registry key and its value data is set to "a":
- The title for the Windows XP Service Pack 1 entry in the Add or Remove Programs tool in Control Panel is changed to "Windows XP Service Pack 1a."
- You can use this entry to remove the service pack. It is present only if you choose to archive files when you install the service pack.
- This entry is not updated if you use the Microsoft Software Installer package to install Windows XP SP1a.
- The title for the SP1a Release Notes has been changed to include "SP1a" in most languages. In other places where "Service Pack 1" is used, the text has not been changed.
Note On the Microsoft Web site, "Service Pack 1" may be used in some cases to refer to either SP1 or SP1a.
Article ID: 813926 - Last Review: 01/09/2007 17:42:00 - Revision: 2.9
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