So, I ditched the method above, as all I could find is the current user...but I needed to search for two user names in the local administrators group.
The following code worked perfectly for what I needed!
Hope this helps someone.
//Get all users from the local Administrators group and create list
DirectoryEntry localMachine = new DirectoryEntry("WinNT://" + Environment.MachineName);
DirectoryEntry admGroup = localMachine.Children.Find("administrators", "group");
object members = admGroup.Invoke("members", null);
List<string> userList = new List<string>();
//Get current user
string localUser1 = WindowsIdentity.GetCurrent().Name.ToString();
//Take domain name off
char[] trimmingsFront = { 'D', 'O', 'M', 'A', 'I', 'N', '\\' };
string trimmedlocalFront = localUser1.TrimStart(trimmingsFront);
//Take "admin" off username
char[] trimmingsEnd = { 'a', 'd', 'm', 'i', 'n' };
string trimmedlocalUser = trimmedlocalFront.TrimEnd(trimmingsEnd);
//Add each local Administrator to list
foreach (object groupMember in (IEnumerable)members)
{
DirectoryEntry member = new DirectoryEntry(groupMember);
userList.Add(member.Name);
}
//Check if users are not part of list
if (!(userList.Contains(trimmedlocalFront)))
MessageBox.Show(trimmedlocalFront + " is not a member of the local Administrators group. The drag and drop functionality will not work unless " + trimmedlocalFront + " is a member of the local Administrators group. After " + trimmedlocalFront + " is added, please restart your machine for the changes to take effect.", "Local Administrator Warning", MessageBoxButtons.OK, MessageBoxIcon.Stop);
else if (!(userList.Contains(trimmedlocalUser)))
MessageBox.Show(trimmedlocalUser + " is not a member of the local Administrators group. The drag and drop functionality will not work unless " + trimmedlocalUser + " is a member of the local Administrators group. After " + trimmedlocalUser + " is added, please restart your machine for the changes to take effect.", "Local Administrator Warning", MessageBoxButtons.OK, MessageBoxIcon.Stop);
If you want to check for your own user names, for the 'if', do:
if (!(userList.Contains(whateverusernameyouwanttosearch)))