When you enable SplunkLightForwarding, Splunk will change a configuration in one of the conf files to disable Splunk web. I don't think the starting splunkweb will work (tried it on my machine and it didn't work anyway). SplunkLightForwarding is basically an App, so it can be disabled (which will re-enable splunkweb).
To see the full output of CMD commands, you may need to CMD as administrator (e.g. right-click the CMD icon and select "run as administrator". Be careful of making other changes!
If you change to the Splunk bin directory (for example on my laptop this is "C:\Program Files\Splunk\bin") for example:
cd \Program Files\Splunk\bin
I would the run the following command to disable the app:
i uninstalled Splunk and reinstalled Splunk before you replied me. i didn't mind uninstalling splunk and i am alright at resuming Splunk at its default state. The info you gave me would come in handy for me. Thanks.