
BS
I have an HP Pavilion a1430n with an AMD64 x2 and I get the endless reboot problem (I was able to go into safe mode to uninstall SP3). Since Windows XP Pro was installed clean (w/ a complete format) off a retail CD it can't be an OEM image issue in my case.
I think I'll wait a few months to have another go at installing SP3. Maybe the ISO trick will work but I'm sick of wasting time patching Microsoft's crappy, poorly-engineered operating systems. I'll install it when they've figured out the issues for sure.