Choosing the OS when dualbooting

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http://askubuntu.com – I've just finished installing Ubuntu, and now have Ubuntu in one partition and Windows 8 in another. I was under the impression that when my computer starts, I would be able to choose from a menu which one to run. However, what happens instead is that Ubuntu runs automatically if I don't press anything, or if I press escape I get a menu which includes only ubuntu and something called memtest - no Windows. How am I supposed to run Windows? Please avoid too much technical language and give me step by step instructions wherever possible. (HowTos)