ph771,
Glad you got it sorted and FWIW here is some more info on the NPE and it's progression (no not a complete history).
I currently have 3 different versions of the NPE in my download folder from previous downloads:
from March 23, 2013 3.2.0.2.3
from Sept 24, 2013 4.0.0.49
from Feb 3,2014 4.0.0.57
I also found information on version 2.0.0.52 which I do not seem to have in my downloads. The removal of this older version does in fact show the use of the Control Panel unistall method of uninstallation - so that's probably where I got it from. Although the information is in an ad for an uninstaller, it does mention registry entires to be removed manually. Remeber I did say in the past. 
These are separate downloads, not associated with the NPE now found with the scan options of NIS (although I'm sure the one with NIS is the most current one).
I also found the following as CV does seem interested in locations:
Starting from Norton 2013, the product initiates a LiveUpdate session and downloads Norton Power Eraser executable to the local computer, when the you select the NPE option on the scan page. Once the download is complete, you can perform a scan using Norton Power Eraser.
The NPE executable is retained on the local computer for future use. When you click on the NPE option upon the completion of subsequent manual scan, it invokes NPE executable from the previously downloaded location.
LiveUpdate downloads and stores NPE executable in the following location:
Windows XP: C:\Documents and Settings\All Users\Application Data\Norton\[Silo ID of the
point product]\Norton point_product_version\
Windows Vista, 7 and 8: C:\ProgramData\ Norton\[Silo ID of the point product]\Norton
point_product_version\
In my win 7 system, [Silo ID of the point product]\Nortonpoint_product_version\ appears to translate to:
C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NIS_21.1.1.7\NPE.exe
Hope this addtional info proves helpful to someone!