After reading replies from several people that ARC500PRO does in fact work for recording, I spent several hours double-checking everything on my PC. All of the hardware drivers & system BIOS were up to date - no changes to be made there (Intel motherboard with on-board Realtek sound card).
Out of desperation, I disabled the digital audio I/O on my sound card (leaving the analog working), doing this by going into the advanced settings of the sound card and disabling any digital audio functions.
I have ARC500 Pro logging/recording for just over 8 hours now with no freeze-up!
I don't know if this will work for others, but it seems to have done the trick for me. I don't use any digital audio devices, but if you do, good luck....