Frustrated about the lack of clarity on the XP and SSE-SSE2 CPU instruction set issue, I queried Norton Support. Here is an excerpt of my chat exchange:
Welcome to Norton Support, my name is K. Please give me a minute to go through the information you have provided.
C: Can you confirm that the current version of NAV 2014 can run on older computers with XP Pro Sp3 having only the SSE CPU instruction set. Or is the SSE2 CPU instruction set now a requirement? And, same question about the current Norton Power Eraser version 4.3.5.28. Thanks.
K: C, please be informed that the Norton AntiVirus latest version is compatible with the Windows XP computers.
K: And also Windows XP is compatible for the latest Norton Power Eraser.
C: That's not my question! Is the latest NAV and current NPE compatible with the SSE CPU instrution set or is the newer SSE2 CPU instrution set now a requirement? Thanks.
K: C, the latest Norton program will work in the old SSE CPU instruction set. It is not required to use the newer SSE2 CPU instruction set.
C: And you are 100% sure that this is the case? It's important that you know this to 100%. Thanks.
K: Yes, I am 100% sure. This will work.
C: Okay, thanks. That's all.
K: You are welcome. It was my pleasure assisting a valuable customer like you.
If the above is the last word remains to be seen, but, if it is I stand corrected in my assumptions that SSE is/was the culprit.