In a scenario when a user wants to install JIRA as the service by executing service.bat and there is no JAVA_HOME, JDK or JRE installed in Windows (clean installation), the service can't start.

I think, the problem is related to a value (auto) that in this scenario is assigned to a JVM key. It is stored in HLM\SOFTWARE\Apache Software Foundation\Procrun 2.0\JIRA<set of digits>\Parameters\Java and it should point to jvm.dll from <JIRA home path>\jre\ or from JAVA_HOME if defined. Although, in the bat file the validation of JVM is done in the following way:

rem Set the server jvm from JAVA_HOME
set PR_JVM=%JAVA_HOME%\jre\bin\server\jvm.dll
if exist "%PR_JVM%" goto foundJvm
rem Set the client jvm from JAVA_HOME
set PR_JVM=%CURRENT_DIR%\jre\bin\client\jvm.dll
if exist "%PR_JVM%" goto foundJvm
rem Check for JRockit JVM: Bugzilla 39674
set PR_JVM=%JAVA_HOME%\jre\bin\jrockit\jvm.dll
if exist "%PR_JVM%" goto foundJvm
set PR_JVM=auto

so we finish up with JVM the vaule auto which can't "find" any JVM.

Attached log file from a test the failed installation of the service.