PC not starting (sometimes)

[Pi rules]

I was trying to improve the airflow and appearance (window on case) of my PC with some tubing, zip-ties, and wire clips (I'll provide links later). When I turned it on and the lights and fans flickered and died (a few milliseconds). So, I turned the switch back off, unplugged all non-essential parts and it worked. So, I plugged in a few at a time and it stopped. I repeated this again and again, and now it works with everything plugged in. My question is: why did it happen?

I have a few ideas:
1. The cables were bent too much
2. A cable was plugged in incorrectly
3. A molex connector was shorting out the PSU

[kelly]

Well, this is not something that you can pinpoint, but here's what may have happened:
Maybe there was a card or connector where the contact was marginal. When you were in there you moved to just enough so that the marginal connection finally failed. Reseating the connection fixed it.
-td

[Pi rules]

That could be it, possibly the floppy drive.

Thanks. :wave:

[Pi rules]

I'm still guessing that it was the floppy drive; the second time I did it, I made sure to use a bright light to make sure I did it properly. What exactly did this do, then, create a short circuit between the 12 & 5 volt?

I did not smell anything different like smoke and there were no visible marks either. Is this just from the PSU exerting overload or over voltage protection before anything happened?