My desktop computer became laggy suddenly

[al3ab98]

Okay I have a decent assembled computer (4GB DDR3 RAM / Nvidia GeForce GT 610 2gb graphics card / Inter core i3 2nd generation CPU / BIOSTAR H61MLV3 motherboard) anyways my computer used to run really fine I (play games surf YouTube etc...) without any problem but now and suddenly it became really really slow. It's like most of the apps I use started to freeze... like for example when I run steam the disk usage gets to 90%+ or google or any game even file explorer (google mostly)... whenever I open a YouTube video it takes a while to load and when I scroll down to read comments it freezes... also I can no longer play video games cuz I get a horrible fps drop, even low end games such as Terraria,CSGO,Mineraft are no longer playable while they used to be really fine in the past ? any solution please
Note: I'm not using any antivirus also I reinstalled the windows several times (reinstalled windows 10 (formatted) and now i'm trying windows 7 but still the same problem).

 

[rgd1101]

old pc, check cpu/gpu temp, hdd health, ram usage.

 

[al3ab98]

old pc, check cpu/gpu temp, hdd health, ram usage.

It's true that it's an old pc, cpu/gpu temp is fine, for the hdd health its status says "Caution" after i checked it with CrystalDiskInfo tool, ram usage is fine as well! as I said the computer used to run really fine and suddenly became like this

 

[seagate_surfer]

al3ab98 , use Seatools to test the HDD as it will give you the health and state of the drive.

 

[al3ab98]

al3ab98 , use Seatools to test the HDD as it will give you the health and state of the drive.

I did and it's saying "Caution" for the HDD status
Edit: I clicked on "Caution" and it brought me "Health Status Settings" tab, I switched everything to 0 and the health status now is saying "Good" I tested a game(CSGO) and it was fine, also google no longer freezes too thx for support!