The first component you see when your Mandriva Linux boots is the bootloader menu. It allows you to boot your GNU/Linux system, or any other operating system installed on your machine, as well as some special options.
The number of items and their names vary depending on your particular configuration. The one labeled linux starts your Mandriva Linux system and it's the default item unless you manually configure it differently. Wait a few seconds or press Enter, and Mandriva Linux starts to load. Use the arrow keys on your keyboard and press Enter to select another item.