simple way to install ubuntu 11.04

First of all ensure u have at least 20 GB of space free in ur hardisk(free means unallocated memory)

Once u do that reboot ur system and boot the ubuntu cd from the boot option or change boot preferences from the BIOS.

Once your BIOS is configured to boot from CD first, if you have Ubuntu in the drive, you should see the splash screen with a ubuntu written on it. Ubuntu will take a couple of minutes to load up. Just be patient.

Select your preferred language.
If you have at least 512 MB of RAM, you may want to select Try Ubuntu, as it will allow you to do other things (check your email, browse the web) while you're installing Ubuntu.
If you have only 256 MB or 384 MB of RAM, you should select Install Ubuntu. This will give you the same installation screens you see below, but you won't have the rest of the Ubuntu live session running as well.
Select your language.
There is a new option in the Ubuntu 11.04 and 10.10 installers that asks if you want to install closed source third-party software for MP3 playback and Flash, for example. I would strongly suggest—unless you know who Richard Stallman is—that you check (or tick) this option.
If you want to install Ubuntu next to Windows so you can choose which operating system you want at boot-up, select the first option. As mentioned before, do this only if you don't anticipate even a small possiblity of returning exclusively to Windows. A traditional dual-boot can be undone but it's not easy.
This is how u do it go to advanced option
Now make four partitions out of 20 gb free partition(if u have free space in extended partition choose partition type as logical)
One for boot with
Mount point as /boot
Filetype as Ext3
And size 300 MB
Next for root (where all system files are stored)
Mount point as /
Filetype as Ext3
And size 7 GB
Then for home directory( where ur main data is stored)
Mount point /home
Filetype Ext3
And size 9GB
Then for swap(ie for memory requirements)
No mount point
File type swap
Size 4 GB
While Ubuntu is preparing files to copy over for installation, it'll ask you some questions. They're self-explanatory.
Eventually, the installation will finish (the whole thing can take anywhere between 15 minutes and an hour, depending on the speed of your computer). You can either Continue Testing if you want to shutdown your computer or Restart Now if you want to restart your computer.
Either way, Ubuntu will eject your CD (or prompt you for when to remove your USB stick, if you used UNetBootIn instead of a CD burning program). The next time you boot up, you should have a working Ubuntu installation!