Wubi installer is one of the best way of installing Ubuntu OS inside windows (You need not make any partition at all). Here are the steps to install: Download the wubi.exe from here . Just double click the file wubi.exe and follow the instructions there of. You may get an error like " Permission Denied " or the software will try to download the ubuntu-xx.xx.amd-x.iso. in either of the above case, download the ubuntu-11.04-desktop-i386.iso and put the file under the same folder where the wubi.exe is stored now go to step 2 for installation. Once the Software is installed, reboot the system and click ubuntu instead of windows and follow the instructions. That's it. Ubuntu is installed inside windows. If you want to delete ubuntu, just go to (Windows 7) control panel -> Program and Features -> right click ubuntu and remove, in windows XP, goto Control Panel -> Add/Remove Programs -> right click Ubuntu and uninstall..