I've got a fresh installation of Tomcat 7.0.56. When I run startup.bat (As administrator or not), I got the following message:
Using CATALINA_BASE: "C:\uPortal_test\apache-tomcat-7.0.56"
Using CATALINA_HOME: "C:\uPortal_test\apache-tomcat-7.0.56"
Using CATALINA_TMPDIR: "C:\uPortal_test\apache-tomcat-7.0.56\temp"
Using JRE_HOME: "C:\Program Files (x86)\Java\jdk1.7.0_71"
Using CLASSPATH: "C:\uPortal_test\apache-tomcat-7.0.56\bin\bootstrap.jar;C
:\uPortal_test\apache-tomcat-7.0.56\bin\tomcat-juli.jar"
And that's it. The console closes instantly. I followed this Tutorial
I set CATALINA_HOME at the beginning of startup.bat, just in case, but it should not be necessary