The common part to all the components you have replaced is the power supply. Maybe it is has a bad output? The link tells how to test Power supply under load (not for a novice)
I found this link in a post on cnet. See link below.
Another problem which may effect component life is poor or no cooling. Do you have the computer in a bad environment? Is there a bad or dust packed case fan? Is the computer housed in a no vent cabnet?
Another problem maybe the AC power from the wall outlet maybe messed up. Bad outlet(worn or loose)that needs to be replaced. Line noisy may require an UPS (Filtering system and battery backup device) can help with this issue. I hope this helps.
I bought a computer last year and it breaks every month.
Nobody can fix it. Some shops fix the harddrive and it goes for a month, sometimes they fix the motherboard and it goes for another month. Last month it had a "read drive error", and someone fixed the hard drive, this month I have "read system error" and also it won't register the keyboard.
All the hardwear is in good condition, but nothing seems to be in harmony.
Any help would be most appreciated.