PC Lagging after some weeks of fresh Windows install

[StavrosWTF]

So I am really confused about this. I am pretty knowledgeable as for PCs and stuff but this is irritating. Every time I format my PC and freshly install Windows, my PC is running smoothly. But after some weeks, it starts lagging. PC doesn't boot that fast, after it has started it takes some minutes to display everything and there are several times that Firefox and other apps crash for no reason (more frequently than expected). I have checked everything (delete junk, remove startup apps, remove animations, defrag disk). The things I must say about my system is that, besides being high performance generally, it has a pretty cheap moba, ddr3 ram and a bad disk (many errors daily).

 

[smorizio]

if you run hdtune and hard drive vendor test tools if the drive fails or has warning it time to rma or replace it.