Thus far, the hardware agent continues to operate normally.
The software agent on the PC began showing pings on the pings graph at the bottom of the dashboard page, resumed speed tests, and reported that the agent was sending updated hops in the recent events section of the dashboard. So far, so good. I've turned the third-party PC firewall back on and, just for insurance, I am going to add an application rule to the firewall to allow ICMP. The firewall can respond (allow or block) to various ICMP messages, so are there any specific ones that should be allowed, or should I just allow all ICMP messages?
FYI, I purchased the hardware agent so that I would not need to have the PC on 24/7 just to have the network monitoring running. Once I feel comfortable with the hardware agent, I probable remove the software agent from the PC
Once again, thanks for your assistance!