The JVM launch parameters of these Windows services are controlled by an XML file jenkins.xml and jenkins-slave.xml respectively. These files can be found in $JENKINS_HOME and in the slave root directory respectively, after you've install them as Windows services.
The file format should be self-explanatory. Tweak the arguments for example to give JVM a bigger memory.
Stdout and stderr from the service processes go to log files in the same directory. Uninstallation
To uninstall the jenkins slave service, run jenkins-slave.exe uninstall from the command line.
To uninstall the jenkins service, run jenkins.exe uninstall from the command line. Troubleshooting
If the slave service doesn't start as intended, check the following locations for more information.
Look at the Windows event viewer under the application section for the logging output from Jenkins. This captures the key Windows service events, such as startup and termination
Look at the log files in the directory that jenkins.exe resides. They correspond to the standard output and the standard error from the slave process, and often Java stack traces are sent there.