Steps to turn off cores: (For Windows 7)
1.) Open MSCONFIG (You can open it by entering MSCONFIG in the search bar)
2.) Select the “Boot” tab
3.) Click on “Advanced Options”
4.) Check “Number of Processors”
5.) Select “1” from dropdown menu
6.) Click “Apply”
7.) Restart machine
Steps to turn off cores: (For Windows Vista)
1.) Open MSCONFIG – Start> Run > Type MSCONFIG
2.) Select the “BOOT.INI” tab
3.) Click on “Advanced Options…”
4.) Select the check box for /NUMPROC= set it to 1 & click “OK”
5.) Click “Apply”
6.) Restart machine