I have installed sitecore 8 in my machine and it is working fine. Now I want to install Sitecore 7.5 on the same machine without disturbing the sitecore 8 instance. I have read that it is possible to run multiple instances of Sitecore on same machine, but how does SQL server databases are used by the two instances.
I have installed MongoDB on windows machine and made it to run as windows service by following these steps. The service has started after running the start command as shown below.