May be a stupid question, but here goes. I want to install a second Splunk instance on my windows machine so that I can have one for doing my stuff and one to show customers for demos. But the exe file only gives me the option to modify or remove my current instance. Do I need to move or adjust my current instance before I can install another instance? How is this done on Windows?
Before version 4.2 you can run the second Splunk instance in the user mode (as opposed to the service mode it's running by default).
Such instance will run while your user session is active.
Not a stupid question! There are many reasons, including getting better performance out of a heavy-duty box, that you would want to run multiple copies of Splunk. Windows installer just doesn't make it easy.
There is a 4.3.x writeup, including new service creation, ensuring both instances are unique, and upgrading the instances, posted here on the wiki.