Problem with Lenovo G710 suddenly acting slow

Added (1). My lenovo G710 is about 4 years old, had no problems so far but recently it started acting very slow in games mostly. Lenovo solution center hardware scan showed yellow exlamation marks for smart short self test and smart drive self test (ST1000LM024 HN-M101MBB), but apparently no problems were detected. Is my HDD failing? Is that why its so slow?

Added (2). Disk usage sometimes randomly spikes to 100% for a moment.

Added (3). I'm running i7-4702mq, gt820m and 8gb ddr3

Guest

Schedule a full disk check see if it fixes it. It will take some time to execute at next system restart. You possibly migh have a small drive and may have filled it up. Check your disk usage and spare disk space. Having less than 10gb of space or less than 10% spare capacity would be a sign to tell you to remove some stuff as your disk is going get slower.

Laurence I