A friend of mine told me that its PC suffer strange behavior, sometimes doesn't reach the Windows welcome screen, or it switch off suddenly during it working or produce weird graphics on its monitor.
Yesterday I got it and the first thing I try is connecting an external USB HDD. It switched off immediately. The same does not happen for example with a Wireless USB dongle.
The computer is more or less 5 years old. My idea is that the PSU has something wrong.
Do you suggest buy a new one, or could be also the motherboard the problem?