I am trying to install Jenkins slave service after starting the slave via web start.
I get the following error when it tries to install on windows 10 and windows 8.1.
Open a command window with "Run as Administrator".
Just in case, You may have trouble with the .jnlp in "Steve Brownell" instructions, then, run the first line of your error message, shown below.
c:\JenkinsWorkDirectory\jenkins-slave.exe install