Right Click on My Computer and select Properties. In the newly opened window, on the left side click Advanced system settings. In the new window go to Advanced tab and under the Performance tab click Settings. In the new window go to Advanced and on the Virtual Memory click Change and after this uncheck Automatically manage paging file size for all drives.
This way you can set the virtual memory manually.
To be able to see how much is used you can use Task Manager. Right click on the taskbar and select Task Manager.