If you are not running Windows XP SP1, install SP1a for security and reliability updates to the Windows XP family of operating systems. There is no benefit to installing SP1a if you are already running Windows XP SP1.
We do not recommend that you install SP1a if you are already running SP1. Windows XP SP1a is almost identical to Windows XP SP1 except that the Microsoft virtual machine (VM) is removed in SP1a.
WHAT’S NEW IN VERSION 1A
What does install from ISO mean?
--An ISO installation file is a collection of individual files and folders on an installation DVD combined into a single file.
How do I work an ISO file?
--You can open the ISO file using File Explorer or Windows Explorer in the pop-up menu. Next, select the disc image burn command. The Windows Disc Image Burner tool should appear and point to your CD/DVD drive. Click the Burn button to continue.
How install from ISO file in Windows?
--Right-click the ISO image file and select Mount from the menu. It will open the file like a DVD. Next, you'll see an entry for your drive letter in Windows Explorer. Browse to the location of the setup file and double-click it to begin your installation.