If the node is ICMP only, then no credential.
If you want to capture identifying information about the PC via WMI, you're going to need some credentials. Even if the PC isn't on a domain, you can use COMPUTERNAME\username (where 'username' is a valid defined user on the PC) as your credential and should have success as long as that user has the appropriate access on the PC.
In the edit node section for the polling method, i did what you stated but it still doesn't work. I input the credentials and click "test" and it fails.
Doesn't work for both users. One is admin and the other is a regular account. For "Credential Name" I tried "Administrator," "User," and "Local Account," but no luck. Any other pointers? I am double checking my computer name, user name, and password and I am not fat fingering anything. In User Accounts of the PC when I pull up the user accounts, it shows the 2 users which are 1 is admin, 1 is not, and both are local accounts with password protection.
Here's where I would start.
First, define whether or not any firewall policies are in play between the poller and the computer you're trying to add. If there are, you'll need to allow the appropriate communication between the two. Based on your original message, it sounds as if ICMP is allowed - but that doesn't mean that all traffic currently is making it. For example, are you able to RDP to the computer using the credentials? If not, it doesn't mean you have the credentials wrong - it could just be that 3389 isn't allowed through the firewall.
This KB's specifically about SAM, but does a good job of enumerating ports required:
Second, what is the OS flavor of the computer you're attempting to poll? Home variants of any of the Windows OSes can require a little extra work to expose WMI.