How to Remove an Operating System From Windows Vista

1. Start the computer in Windows Vista and log in to an account with administrator-level access.
2. Click the 'Start' menu, then select 'Control Panel.'
3. Type 'Advanced system' into the search box at the top of the Control Panel. Then click on 'View advanced system settings.'
4. Click the 'Advanced' tab at the top of the dialog box, then click 'Start and recovery.'
5. Click the drop-down menu labeled 'Default operating system.' Select 'Microsoft Windows Vista,' then click 'OK' to save the settings.
6. Click the 'Start' menu, then right-click 'Computer.' Select 'Manage' from the list of options.
7. Click 'Disk Management' from the left column.
8. Locate the partition that contains the additional operating system. Then right-click on the partition and select 'Delete Volume.' Click 'Yes' to confirm that you want to delete the volume. The additional operating system is then removed.