An issue with how the Service Pack 3 update handles AMD chips will cause some Windows XP computers to continuously reboot. Microsoft says it is investigating, and provided removal instructions for those having problems.
The issues come in two forms: The first affects some systems with AMD chips and OEM XP images, while the other seems to affect certain AMD motherboards. Microsoft is looking into the problem and said it will advise when it has a solution.
There is a chance that the first issue could occur on some Intel machines as well. This is due to the same image being used on that machine, which is actually more the manufacturer's error than it is Microsoft's.
At the heart is likely the power management system file, intelppm.sys. Some of these OEM images may be shipping with both the AMD version, amdk8.sys, alongside the Intel file -- which Microsoft says is an unsupported configuration.
Some users experienced similar problems when SP2 was released, so this could be the problem. If the user sees a stop error code of 0x0000007e, this first issue is likely the reason why the computer does not boot properly.
The second issue will only occur on systems with certain AMD motherboards. This error manifests itself with an error code of STOP: 0x000000A5. It is unknown how to fix this problem other than by installing a USB storage device, or even possibly removing a USB mouse and replacing it with a PS/2 port compatible version.
If that is not enough, Microsoft MVP Jesper Johansson reports that there seems to be a third, less common problem with SP3 computers, this time on Intel. Some may receive a 0x00000024 stop error, which he believes may be due to an issue with either the NTFS file system being corrupted, or a faulty video driver.