Thanks again for all the advice. I have cleaned up my fans, PSU and the dust filters with a brush for now. Managed to get most of the dirt away (I realized that I haven't cleaned my computer in ages =_= ). I will try out the thermal paste and the other stuff once I managed to buy them. Regarding the CPU cooler: Do I replace it with the exact same model? Or is there a better model I can get? Any recommendations? (80 AUD is ok for me. I am looking for something below 120 to 130 USD if possible.) Regarding the Memtest: I finished Memtest for one stick. It finished 7 tests without a problem. (I think this is the only good news so far, haha). Total run time is 4 hours 50 minutes. Gonna post the results of the next stick tomorrow. Regarding the CPU: I was thinking of at least replace the CPU Cooler first. If I have to replace the CPU Cooler, Ram and also the CPU, I don't know whether is it better off for me to replace the entire com. But I think I will try with replacing cooler and RAM (If the RAM has issues) first. Also, I will try to get another HWInfo high load for 30 minutes tomorrow. Maybe all that dust clearing can give me some better results.