Gaspershooters -
Thanks for the tip - that was apparently it. As it happens, I ended up with ASC installed by stealth once a few months ago when I installed Smart Defrag. One of the reasons I ended up ditching it - I don't like that sort of behavior. Uninstalled with Revo but even Revo didn't get rid of this little gem.
Found updatepackasc.exe in C:/Users/{username}/AppData/Local/Temp and a copy of it in Prefetch. It had a file creation date of 6-19-14 so I presume the Iobit remnant app which generated it had a date trigger.
Then found two Iobit folders remaining in C:/Users/{username}/AppData/LocalLow and another Iobit folder in C:/Users/{username}/AppData/Roaming.
Needless to say, deleted them all. I was pretty pissed at Iobit's behavior previously and with problems encountered with the version 3 update of Smart Defrag, but now I despise them for their intrusiveness. Cost me a full half day of work today, the bastards (wasn't about to do anything on my rig until I 'cleared' this issue). Wouldn't trust anything from them or their 'partners' and would consider their products to be malware. YMMV
EDIT - I've calmed down a bit now. The malware accusation was probably uncalled for but I would still be cautious with their products.