I’ve been there. there is no problem with the operating system you are using. it is because the SD card gets problem.
there are quite a few solutions I found online and I believe there must be at least one that can fix the problem, such as format it at Disk Management, using command line or check and repair bad sectors.
http://www.eassos.com/how-to/windows-was-unable-to-complete-the-format.php
For me I prefer buying a new SD card, as SD card can’t be completely repaired. (One of my friends whose work is repairing computer told me).