A typical way to expand the system RAM digitally is by managing the size of the PageFile. By default, Windows uses the RAM memory to temporary store the applications and their information and then expand to the pagefile which is actually a file. To make more room for an application that requires more RAM, simply increase the PageFile although you will find that other apps will behave differently when the amount or RAM decreases.
Go to Start > Run and type control sysdm.cpl. Switch to the Advanced > Settings > Advanced > Change. Increase the size of the page file based on your ram. Typically it should be 1.5x the total amount of physical RAM installed on your PC. Use 3x as a recommended settings and then check the behavior. Adjust the setting as necessary.