The hard drive has failed to recovery data from it see here:

http://dellwindowsreinstallationguide.com/data-recovery-using-fedora/

https://www.youtube.com/watch?v=arX7DUWGCvM

Once you have Recovered your Data it needs to be replaced preferably with a solid state drive. Crucial have compatible parts, refer to the Service Manual for installation instructions. Unfortunately this system wasn't built with easy access to the hard drive so pay attention to the service manual which will instruct you in removing and replacing the hard drive:

http://www.crucial.com/usa/en/compatible-upgrade-for/Dell/inspiron-n5110

http://ftp.dell.com/Manuals/all-products/esuprt_laptop/esuprt_inspiron_laptop/inspiron-15r-n5110_service%20manual_en-us.pdf 

After you have replaced the broken drive with the SSD follow the instructions here to Download and Clean Install Windows 10 TH2:

http://dellwindowsreinstallationguide.com/download-windows-10-oem-and-retail-iso/

https://www.youtube.com/watch?v=ycGr3MBcAnw&list=PL1RkaknDn7v-Ucth4gt0U3BHVSY7oNkWr&index=5