After installing new hard drive, getting insane lag

[doxumentary]

Hello,

I have a mid-spec gaming rig that i ordered prebuilt from Cyberpower (a mistake, I know) and customized a little. I have an FX-6300 and a 7850 2gb. Usually I'm able to run most games at max settings at 1920x1080. For example, I was getting about 120 fps on CS:GO with it maxed out (I know it's not a demanding game, but this is just an example). However, after installing a new 2TB hard drive to go with my other 500gb, I moved all my steam games and some music to the drive. At first, I noticed no difference, but after about a month, my games have been suffering. Now I can only get about 30 fps on CS:GO on lowest settings and for god's sake, I can barely run Minecraft. Also, after leaving my computer on for a while, windows explorer seems to crash or something, and my start bar doesn't work, and n buttons show where they're supposed to. I was wondering what I should do to fix these issues or if I should just reinstall windows.

Thanks

 

[Mattios]

Try running a malware scan http://malwarebytes.org

 

[doxumentary]

Try running a malware scan http://malwarebytes.org

I have done so and nothing was detected.

 

[fzabkar]

Test your RAM with memtest, and test your HDD with a tool such as CrystalDiskInfo or HDDScan.