Pc lags a lot every now and again

[Thegamerwannabe]

so I have no clue what is going on. Whend I bought my pc 3 months ago it was running perfectly but 3 weeks ago it's started lagging massively to put it into perspective when I clicked on my home icon on windows 10 it too my literally 2 h to open up. This lag comes and goes and I have no clue what is causing it, my cpu runs cool it's getting used 100% and my mobo is 40 •C constantly. Please help me out.
Specs: i5 4690k
MsI r9 390
8 ram
MsI z97 mobo
And windows 10

 

[Milheim]

Defrag your hard drives and do a proper virus/malware scan.

 

[captaincharisma]

most likely malware. download malware bytes and run a scan to scan for malware. you may have some viruses as well so you would need a virus scanner

 

[geofelt]

When you installed windows 10, did you pay attention to the privacy options, or did you select the default??
Google "windows 10 privacy issues"

The default , among other things, can turn your pc into a server to send out updates to other pc's
Here is one discussion on that issue:
http://www.slate.com/articles/technology/bitwise/2015/08/windows_10_privacy_problems_here_s_how_bad_they_are_and_how_to_plug_them.html

 

[captaincharisma]

even with the default settings on it would not lag down a pc like that

 

[Thegamerwannabe]

Defrag your hard drives and do a proper virus/malware scan.

How do I do that