This may help:

1. Set a restore point (if you can).

2. Run this command from Command Prompt (Admin):

dism /online /cleanup-image /restorehealth ("and wait for this command to complete").

3. Re-Run the sfc command.

Thanks MAXD I will go and try this now and I will come back when I'm finish.

Ok I'm back. This is what happen. First I set a restore point I think:emotion-2: Then I ran the cleanup-image/restorehealth and this is what it said "The restore operation completed successfully. The component store corruption was repaired. Then I did the sfc scan again and after the scan it said " Windows Resource Protection did not find any integrity violations". After that I went to pc setting and tried to restore the tablet back to factory setting and I got the same message " some files are missing. need windows installation or media. I'm at my wit ends on trying to restore this tablet. Any other ideas?

Thanks so much for all of your help. I really do appreciate it.

Haven't really helped you but I'm trying. What its actually looking for, i find out, is the installation files. You may have to download them and copy to a flash drive from this linK:

http://windows.microsoft.com/en-IN/windows-8/create-reset-refresh-media

Can't believe the smarter chaps here haven't posted the solution to this; have you checked the site thoroughly ? If anyone knows please jump in. In any case I'm still looking for a precise instruction set for you to work from. I'm not even sure this is doable; may need to return to dell for a fix and then go from there. I'm assuming you attempted a refresh as well and got the same 'missing files' error.

Will review more tomorrow if no one comes up with a solution; have you asked a Dell rep to comment on this ?

Thanks for responding, I will try this tomorrow. I have search here on the site and someone said to try and turn table off and on and this would do the trick but when I did it it kept saying that the computer haven't been shut off correctly. I have not contacted a Dell rep yet because I had to send my tablet to them in Jan of this year and they did fix whatever the problem was so I didn't want to send it to them again. . My tablet is only 5 months old.

Tip: Make a System Restore point before all major changes; if possible make a system image to an external drive (flash or external HDD).

Apparently this usually happens when a system was upgraded to Windows 8; wondering if the (major) Update 1 to 8.1 caused this problem by moving the location of install file or other change. If so I would first set a restore point and then either try to uninstall Update 1 (if possible) Or use Restore to roll system back to pre-Update 1. This is not without its own risks.

To uninstall Update 1: http://pureinfotech.com/2014/04/16/uninstall-windows-81-update/

Couple of tips:

From what I've gleaned you need to be using a MS, not Local, Admin account, possibly be online AND encryption-whether its on, off or paused may play a role. (Is anything sticking ?- LOL).

Did you make a new (MS) Administrator account and try using that account? Try it.

Berserk fixed his problem but systems are not identical, ie RT, so can't use it verbatim:

http://commweb-ps3.us.dell.com/support-forums/mobile-devices/f/4586/t/19494490.aspx

These two site pages appear to agree to the (similar to Berserk) solution; somewhat Advanced and difficult for me to walk you though it:

http://www.tecflap.com/2012/05/07/reset-windows-8-dvd/

http://pureinfotech.com/2013/01/28/fix-insert-media-some-files-are-missing-windows-8/