Try this.
1) Click the "Start" button in the bottom left hand corner of the screen.

2) Select the |"Control Panel"

3) Click the "System" icon within the "Performance and Maintenenace " section

4) Select the "Advanced" tab across the top

5) Click "Settings" within the "Performance" section

6) Select the "Advanced" tab

7) Near the bottom there is a "Change" button, click this

8) Within the "Virtual memory" section there is a button "System managed size"

9) Click this and then the "OK" -- 3 times, to exit the settings.

Restart your machine and STANDBY is once again an option.