Boot Loader tweaking
Right click on My Computer, select Properties. Select the Advanced tab, then the Startup & Recovery button.
Use the Default operating system drop down menu to select the Default Operating System to be loaded during boot-up. This default operating system is loaded assuming a different choice is not selected in the Boot Loader or the timeout for making a selection expires.
Display list of operating systems for. Tick this setting to enable a list of bootable Operating Systems to be displayed during boot-up & the amount of time (In seconds) that the list will be displayed for before loading the Default operating system. This menu can be used to select which Operating System to boot-up each time you start your computer.