I've downloaded the iso for ubuntu, put it on a bootable usb stick, installed ubuntu alongside windows 7 (allocating disk space during the installation, taking it from the hdd on which my windows 7 is installed). Installation worked fine but after rebooting it always starts up windows 7. no bootloader menu is shown during booting and inspecting the boot devices in my bios only lists the hdd that should now contain win7 & ubuntu.
What do I need to do in order to boot ubuntu/display the bootloader menu when i turn my computer on?