Firstly Ubuntu 9.0 is outdated. Download the latest version of Ubuntu
http://www.ubuntu.com/download/desktop or the latest Linux mint
http://www.linuxmint.com/download.php.
Then you'll want to partition your hard drive, You can do this from the linux live media but I always do it first. Select how much drtive space you want for your Linux partition, with Linux you can also make a swap partition. A swap partition is basically used if you run out of ram, but if you have 4gb+ of ram you don't really need a swap partition. Go to disk management in windows, select for main partition, then select 'shrink' enter the size you want your linux partition to be. If Linux is just something you want to play around on then 40gb is plenty. So in the shrink disk box you would add 40000. And if you have less than 4gb of ram and need to create a swap partition it needs to be twice the amount of your ram in size, so if your had 1gb of ram you'd create a partition 2048 in size.If you're going to use a CD to install Linux, download imgburn and burn the ISO at the slowest speed. I'd recommend installing via a usb flash pen. Download
http://unetbootin.sourceforge.net/ make sure your usb pen is formatted to fat32, launch unibootin, select browse for ISO and select whichever linux version you're using, then select your usb pen, then click ok. This will take about 5 minutes ish.
Once unetbootin has finished making your usb pen bootable (or once you've burnt your disk) Reboot your machine and change your machine to boot from either usb or CD first. You'll then be presented with the unetbootin menu, just hit enter on default. You Linux distribution will now boot into a live environment. Once you're at desktop you'll see an icon on the desktop saying either install Ubuntu or install Linux mint, double click that, then click next. You'll now be presented with some options. 1. erase disk and install Ubuntu/mint . Install Ubuntu/mint alongside Windows 8. The option you want to choose is the bottom one which says 'something else' You'll then be presented with the partitioning tool. Look for the partition you created earlier for Linux, double click on that partition. Select use this partition, select file system type EXT 4, select mount point / check format the partition, then click ok. If you crated a swap partition, double click that, select EXT 4 for file system and in the drop down where you selected mount point / earlier select 'swap' this time. But like I said if you have more than 4gb of ram you don't need swap.
Now click on the partition you selected for the Linux partition and select next, if you didn't create a swap partition it'll warn you, just click continue anyway. Then just follow the prompts to enter you language, username and password. Then just sit back while linux installs
When you reboot your computer you be presented with the Linux bootloader which is called GRUB. it will be a black back ground with a list of operating systems. You'll see Ubuntu/Mint in the list and also Windows 8. Select Ubuntu/Mint and once you get to desktop install all your updates and additional drivers. That's it.
Edit: If you ever want to remove Linux, just boot windows 8 into repair computer mode (Not sure how to do that on 8 but somebody will help you) Selects command prompt and type in these two commands hitting enter after each one. command 1: bootrec.exe/fixmbr then hit enter. Command 2. bootrec.exe/fixboot. Then reboot your computer, go to disk management, delete the partition you created for linux, then right click on your windows partition and select 'Expand'. Done.
