Here, I'll help ya out :)
Download From Piriform (https://www.piriform.com/defraggler/download/portable) Portable version. Just run from ZIP file and delete when done. No install required. (Only like 4.5mb)
This is a sample of what it looks like. There will be a little pill icon labeled HEALTH. Once you click there, it will show you the Real/Threshold/Raw data. What we're specifically lookin' for are two rows, Reallocated Sector Count and Reallocation Event Count. Hopefully both these Real values are zero. There's other ways to look at the information provided by this, but for most end-users, these are the two major ones indicating cyclic redundancy (like when a record player skips and plays the same bit of music over and over...) and the most common culprit of unusual latency.
(http://i.imgur.com/PVKtEte.png)