The hard drive is going to fail for sure either sooner or later, but its a good idea to take a new hard drive and replace it with the old one.  You can use the Windows 8 installation CD/DVD to reinstall Windows 8 in future. If the system fails suddenly and you haven't taken any backup of important files, creating full system image is always recommended.  Good Luck!!
 :emotion-9:  I have a dell vostro 2520 laptop that is only 2mths old, already i am getting short self test failiers when ever i perform a HD test!.It is still functioning fine, however im worried that it will go at any time!  The diagnostic test via (f12) after boot also fails the harddrive but passes everything else! i have the windows 8 recovery media disk os only, that came with the laptop,resource and media cd and have back up on a data traveler!.Im not that good when it comes to pc's but im learning! can i use any of the disks i have to re-install win 8? or if i make a system factory image can that be used? any help regarding these issuse's  would be great! im not that familier  with computers as ive said already how do i do a more thorough test to find out exactly what it is causing the problem? thanks for taking the time to read this and giving me your input. :emotion-2:Dee.
Hard drive short self test fail & how to recover my data if HD packs in, also 
how 2 recovery win 8.