Powershell & C# to check if host available

Hi All,

I have a c# code segment which process a power-shell script. The following is the code segment.

Runspace objRunspace = null;
objRunspace = RunspaceFactory.CreateRunspace();
objRunspace.Open();
PowerShell powershell = PowerShell.Create();
powershell.Runspace = objRunspace;
powershell.AddScript("my powershell script");
Collection<PSObject> objPS1 = powershell.Invoke();
if (objPS1.Count == 0)
   {
	//I Assumes that the PC is down
   }

In this case, If the login credentials are wrong or if that particular PC is not available; the ObjPS1.count will be zero. If that count is Zero, I assumes that the host is unavailable. But in accuracy point of view, I want to identify both these (wrong credentials / host unavailable) situations separate. Is there a better way or different approach to achieve the same.

Thanks in advance
Sebastian