I saw some members having trouble in installing Linux on system. This is step-to-step guide for installation of Linux. There are basically following type of users: -- Who want only Linux in their system. -- Who want to Dual-boot Windows & Linux. -- Who want Triple boot Mac, Windows & Linux.(Mac Installed First) --> Installing Only Linux in the system :: Well, This is cake walk & probably everyone will be knowing how to do it. Still for the sake of this post I will cover this noob topic. Insert Linux CD/DVD in the CD drive or Insert Bootable Linux Pen-drive During booting, The setup of Linux installation will start. Click on "Install Linux(whatever distro it is)" Installation will start After Installation gets completed, PC will re-start & Linux is installed in your system. --> Dual-booting Linux & Windows (Windows is already installed) Well, Windows is already been installed. Now make sure one whole entire Drive is kept empty. (Drive D or Drive E whatever you want) Insert Linux disk in CD drive & Re-boot the system The Installation wizard will display after Reboot Most probably there will be three options i) Install Linux alongside Windows ii) Replace Windows with Linux iii) Something else Click on "something else". You might notice there is first option saying "Install Linux alongside Windows" then why we are manually partitioning , right ? In past I had very trouble in auto-installation .. so i prefer manual partitioning & I suggest you to do same. After clicking "something else", you will see hard disk partition. Select that empty drive that you kept for Linux installation. If Partition is not free, then make it free by deleting it. Now, Click "Add" button , you will see "Create partition" In that go to mount point place then select / --> Allot 30-35 GB (This is more than enough) /boot --> Allot 250 MB (More than enough for Kernels) /Home --> Allot the space as per your utilisation (I always keep it around 45-50 GB because I store most of my useful data there) Now give "swap area" :: Go to "use as" & select "Swap area" Allot 2 times your Ram size space .. for 2GB give 4096 MB (Hope you're getting the idea) Click on "install now" After installation PC will boot & you will see Grub boot loader with Linux & Windows selection option .. choose any OS that you wanna load . --> Triple Booting Mac, Windows & Linux :: Mac OS is already installed .. so Mac & Linux boot loader will try to get over eachother. 1st partition should be containing MacOS (Obviously) We need 3 more partition (For windows, Linux & Linux swap- incase linux gets out of memory) Before starting Install rEFIt Boot menu for Mac We wont be using bootcamp as we are triple booting Click on Macintosh partition HD. If there are multiple partition, select one from which you wanna steal some space .. After then hit "+" sign below inorder to create 4 partitions. Click on first new partition & on right side type "Windows" format it to MS-DOS & make size that you want. I usually use just 12-14 GB for windows as I dont have any use of that OS (except my parents who use them a lot) Do same with Linux & Linux swap keep 50 GB space for Linux... and format both to MS-DOS.(Size may differ as per your hard-disk space) Hit apply & you are done. Install Windows & install Ubuntu after Windows. If windows is installed then directly move for installing to Linux. Insert Linux Disk. Click on "something else" In partition , select 50GB space (It would be named as /dev/sda4) .. double click it .. edit the partition .. click on "use as" & click" ext4 journaling system" .. after that click on "format the system" .. and after that in mount point give "/" i.e Root. Now double-click on 2GB space are and use it as "swap area" then click ok. re-check that boot loader is in the partition in which you installed Linux. Click "Install now" Re-start the PC & in GRUB boot-loader you will see all three Operating systems.