Abnormal behavior of PC

[xrs_b]

Recently due to power fluctuation, my PC restarted. Now it started showing some abnormal behavior
sometimes it just keeps restarting at boot screen.
sometimes it works fine.
sometimes it restarts aftter 5-10 mins (checked CPU fan, it is working)
Sometimes it gives disk read error.
Earlier i thought of faulty RAM, but sometimes it works fine. I am unable to pin-point the problem
What could be the problem? Please help me out, so that i can replace faulty part.

 

[turkey3_scratch]

Power supply probably, if not the motherboard. What are your full specs?

 

[xrs_b]

Power supply probably, if not the motherboard. What are your full specs?

Specs of my PC are
AMD FX4100 3.6GHz
RAM 4GB 1333
500GB HDD

 

[turkey3_scratch]

You left out a ton of components. Motherboard, power supply, graphics card.

 

[xrs_b]

You left out a ton of components. Motherboard, power supply, graphics card.

Gigabyte GA 78LMT S2PT motherboard
HIS ATI HD 5450 1GB Graphics card
400W power supply (cheap one)

It was working fine from past 2 years

 

[turkey3_scratch]

Replace the power supply, the fluctuation must have damaged it. Buy a good one.

 

[xrs_b]

Replace the power supply, the fluctuation must have damaged it. Buy a good one.

Thanks, i'll try that