RE: SMART extended self test failed first then hardware failure
Your hard drive may be failing. I would suggest you to backup data on the system. You can try following steps. Please follow the steps mentioned below and then try reinstalling the operating system.
Boot into your Windows 7 or 8 installDVD
Select repair your computer, it will fail and then select the command prompt after a few windows.
Type into command prompt (NO QUOTES)
"list disk" (enter)
find your HDD (in my case disk 0)
"select disk 0" (enter)
Note: Please backup all data from the system to perform the above steps.
Please let me know if this helps.