Hi,
CMD often says disk health okay despite being not.
Please download and run HDTune Trial or HD Tune Free.
http://www.hdtune.com/
Select the Disk where OS is installed.
Make screenshots of the following
the health.
the error scan.
the benchmark.
Post back the screenshots.
Disclaimer:
There are links to non-Microsoft websites which would provide accurate and safe information. Watch out for ads on the websites which are frequently classified as a PUP (Potentially Unwanted Products). There is no need to buy paid products to fix your computers as they do more harm than good sometimes.