I have recently installed Windows 8, Windows 7 and Mac OS X Mountain Lion in my x86 pc. I am using Windows 7 boot loader as my boot loader. There are three entries in this bootloader i.e. Windows 8, Windows 7 and Mac OS X as usual. But sometimes when I start my pc it directly boots Windows 8 without showing any boot loader option or OS choice. Sometimes it shows bootloder option. Why this strange problem? Any idea?