Is your system randomly crashing, rebooting, freezing, etc? Then here are the right steps to resolve the issue:
1. Consider the make & model of your computer system. A cheap, generic or underspecified computer system can be the cause of many stability-related issues or even damage other components.
2. Have you tried running Memtest86+ overnight? Download it, burn it as a CD, and boot to it. It'll automatically start testing your RAM. Even one memory error is too much and will cause system instability or even data corruption. This could indicate faulty memory, voltage irregularities, incorrect timings, overheating, or even a problem with the CPU or motherboard.
3. Capacitors, or caps for short, are like small batteries. They can also fail in the same ways; swelling, leaking out of the top or bottom, or even exploding in severe cases. This can cause voltage irregularities and system instability. Unless you are already skilled at electrical repair, it's almost always best to just replace the entire component.