For example you have installed Windows Vista over Windows Xp and then later deleted Windows XP, but the name of XP still appears in the boot list or grub. You want to delete that extra name from the start windows which asks you to select which operating system to start.
1. Type command ‘msconfig‘ in run (XP) or Start Search (Vista) and press enter.
2. A system configuration window will pop out, click boot tab.
3. Here you will see the list of all the operating systems installed and some other remarks that help you decide which one is which.
4. Select the operating system name that you want to delete from boot list or grub.
5. Click delete.
Note that you cannot delete your default operating system, moreover, you can make anyone as default operating system. You can also set the timeout of the startup boot menu list and many other options related to boot. This is a really helpful tool and solves most of your boot problems or requirements.