My PSU was making a lot of noise with the fan so I removed it and checked for any cables that were standing in the way, but I found out that the axis of the fan is not well aligned and so it tumbles. I put it back because there is nothing I can do about it apart from replacing parts.
After this, when I plugged things back and turned the computer on, I started getting hard drive problems; they are totally random, sometimes the whole system freezes after five minutes (input stuck, audio buzz) and I have to force the restart, sometimes it freezes at Windows load screen, some times works for hours and then fails.
From time to time, after the error occurs, the system at startup goes at the "No bootable device found" black screen, but when I enter the BIOS the HDD is listed. The original SATA cable of the HDD was lose, I used another one without the clip, the system seems to be more stable with it (it doesn't freeze as often), but it still fails.
How can I troubleshoot this problem and find out the source? I did not mess with the PSU, but I might have touched something accidentally somewhere?