Freenas 11.2 rebooting even with no activity

[creynaga]

Hi everyone! My first post, happy to start using freenas despite my current situation.

This is my issue:

I could install freenas 11.2 with usb drive (BIOS option due my old hardware). Everything went super well after configuring the hardware, pools, etc, but after few hours using freenass the pc started to reboot. It might seem that reboots when I transfer large amount of files, but I can't say this for sure. When I do not transfering nothing is more stable, but not 100%.

I'm using a very old PC:

Motherboard: Asus P5QC
CPU: Intel Core 2 Quard 9550 2.83ghz
RAM: 2x 4GB 1333mhz
PSU: Vitsuba 550watts
Ethernet: On board

Could anybody suggest what might be wrong or what should be the first step to isolate the error and fix it?

I do not have spare hardware to replace, so I should buy extra hardware but not sure if there is a way to figure it out what is wrong before buy something.

Thanks!