Missing Operating System - Windows7 - Boot from USB

I am using an HP TouchSmart 600 that came from factory with Windows 7 Home Premium 64-bit. I have decided to get rid of it and installed Ubuntu 14.04 booting from USB and everything went perfect. Now, I want to install again Windows 7 so I downloaded the ISO image from the web and created a bootable USB using YUMI from pendrivelinux.com (my CD/DVD does not work and I don't have original windows CD) after reboot I keep getting this message "Missing Operating System", then Ubuntu is loaded normally.

I have been working to solving this for several days already and tried everything in the forums but nothing worked for me:

1. I have downloaded many different ISO versions from the web to make sure the files were not corrupted.




2. I have formatted the USB with gparted in NTFS and also in FAT32 before installing the ISO and I have also tried to boot in all possible usb slots to make sure I am using the primary one.




3. I have updated the BIOS to boot from the USB device as a very first option.

PS: Please note I am not using any partition, I just want to install Windows 7 back in my machine and after that I will probably use dual-boot to keep using Ubuntu. I wanted to add how the USB looks like but when I run the tree command from terminal is a very long file so just for your reference this is what I can see in the root: I have 6 folders (boot, efi, sources, support, upgrade, yumi) and 4 files (autorun.inf, bootmgr, bootmgr.efi, setup.exe)

Please do let me know if you need any extra information from my side.