Ok for some installing Linux along side Windows and dual booting between them is easy to do. For most of us it's something we have never done before and so is beyond us. Anyway along comes
Wubi that does all the hard work for you. Wubi is a downloader and installer for
Ubuntu.
Basically you download Wubi and run it. Wui creates a virtual partition on the drive of your choice and you can even specify the size for the virtual partition. On running Wubi it will ask you what drive to put the virtual partition on, how much space to use for it, what language to use, which type of Ubuntu to install (Gnome, KDE, KDE 4 remix, or Xfce but I suggest Gnome for people new to Linux), and for a username and password. It then downloads the Ubuntu you have selected and installs it. Once installed you can reboot your computer and at start up you will get a screen asking if you want to boot into Windows or Ubuntu (if you do nothing it will automatically start Windows after 30 seconds). And that's it. No damage to your Windows installation, no loss of file and if you want to un-install it just boot inWindows and run Wubi again.
I've been using this for a coupe of weeks now and mostly find myself using Ubuntu. The Gnome version (which is Ubuntu, KDE version being Kubuntu and Xfce version being Xubuntu) comes with Firefox 3 (web browser), Open Office 2.4 (office suite like MS office), Evolution (Outlook like program with mail and calendar), GIMP (graphics editor), an audio/video player, loads of games, cd/dvd burner etc. It does not come with avi playback nor mp3 playback but when you go to play one of these files it will tell you it needs the codec then offer to install it.
I personally don't use the default programs and instead I have instaled Amarok for listening to music, VLC for watching films and Thunderbird for reading email. Software is easily installed by using the Synaptics package manager which lists all available software and you just tick what you want to install (or untick if you have it installed and want to remove it) and click apply. it's that easy.