I had an occasion when I was trying to install Ubuntu 20.04 onto a laptop but found that I was without a usb pen drive, external usb drive or a recordable DVD media and had no way to easily get any so I tried installing Ubuntu without installation media and this is the technique that worked for me:

To install Ubuntu without CD/DVD or USB pendrive, follow these steps:

1. Download Unetbootin from here.
2. Run Unetbootin.
3. Now, from the drop-down menu under Type: select Hard Disk.
4. Next select the Diskimage. Browse to the directory where you downloaded the iso file of Ubuntu.
5. Press OK.

Install Ubuntu 20.04 from the hard drive:

1. Next when you reboot, you will get a menu like this:
2. Select Unetbootin and you will get the “Try” or “Install” option there.
3. Finally, you can install your version of Ubuntu alongside Windows.

For UEFI devices:

• First, download rEFInd.
• Then, extract it.
• Now, follow the below steps to install rEFInd^[source], so that, you have a boot menu to boot to Ubuntu Live environment. Summary of the installation process given in the source is as belows:
  1. Open cmd with Administrator privileges.
  2. Then,mountvol S: /S
     • (you may change S: to any available drive letter)
  3. Type cd in cmd and then drag and drop the extracted folder to the already open cmd window. E.g.,cd "C:\Program Files"
  4. Copy refindxcopy /E refind S:\EFI\refind\
     • In this step S: will be the drive letter that you used above.
  5. Change directory to rEFIndcd S:\EFI\refind
  6. Rename config filerename refind.conf-sample refind.conf
  7. Note that {bootmgr} is entered as such; that’s not a notation for a variable. Also, change refind_x64.efi to refind_ia32.efi on systems with 32-bit EFIs. Such computers are rare, and most of them are tablets. Check your Windows bit depth to determine which binary you should use.bcdedit /set {bootmgr} path \EFI\refind\refind_x64.efi
  8. Download EaseUS Partition Master Free and run it.
  9. Select your last partition.
  10. Right-click on it and from the context menu select Resize/Move partition.
  11. From the size shown beside Partition Size minus 4096 MB (to mimic a 4GB pendrive).
  12. Press tab and the rest will be auto-completed.
  13. Select the newly created partition and right-click on it. Select Create Partition from context menu.
  14. In this window, select FAT32 as the File System. Click on OK. Finally, click on Apply (present at the top-left of the window).
  15. Next, extract Ubuntu iso to this partition and finally reboot.
  16. You will be presented with a rEFInd menu. From here select the Ubuntu partition. It will boot into a Live environment. Continue with the installation. After the installation finishes boot to Windows.
  17. Run EaseUS Partition Master Free again.
  18. Right-click on the 4 GB partition and from the context menu select Delete Partition.
  19. Right-click on the partition above the Unallocated partition and select Resize/Move Partition from the context menu.
  20. Extend the bar to the extreme right by dragging the button.
  21. Click on OK. Finally, click on Apply (present at the top-left of the window).
  22. Open cmd with Administrator privileges.
  23. Then,mountvol S: /S
      • (you may change S: to any available drive letter)
  24. Remove rEFIndrmdir "S:\EFI\refind" /S /Q
      • In this step S: will be the drive letter that you used above.
  25. Reinstall grub as your primary boot managerbcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi

The machine will then boot into Ubuntu.

For more Ubuntu posts take a look at our Ubuntu category.