The recovery disk doesn't contain the operating system.It allows you to access the recovery partition on the hard drive. If you install another operating system that usually makes the restore/recovery partition unusable. You cannot use the recovery disk to install windows 8 after installing another OS.. If you used Dell Backup and Recovery, you might have other options if you chose to copy the Factory Restore partition to the thumb drive. Boot to the recovery flash drive and see what you can do. You can test it out without actually reinstalling anything. To reinstall windows 8 you most likely will need to request the disks from Dell:  [URL]
I have a dell inspiron 15r turbo se (7520) with pre installed windows 8. I am a big fan of Windows 7 rather than Windows 8.So i would like to completely remove windows 8 and install fresh windows 7 ultimate. My problem is now that in future if i like to install windows 8 then will the recovery disk help me do that ??. Please help me.
Install windows 8 using recovery disk on windows 7