Upgraded Power Box, Failure to stay powered on

[Jidt]

I recently upgrade my computer's power from 350 to 500, but now it refuses to remain powered on for more than a couple seconds. The first time it remained on for 5 minutes, long enough for me to get a game running, but then it shut off, and now when I power it on it makes a sad whirring hum, then turns back off.
I decided to have some help putting in the thing, since I'd never done it before, but I am skeptical of the individual's skill, as he went off a youtube video as he did the transfer. (Not that I have anything against tutorials, but if you're advertising as a computer hardware technician, it doesn't really help your credentials.)
     So I'm wondering, is it the hardware installation that sounds like it's an issue, or would it be compatibility with the other parts? I don't have a lot of knowledge regarding hardware, so I'm just looking for some help regarding the identification of the issue. Thanks!

[DaveLembke]

What make/model power supply for the 500 watt?

Is it brand new or one that was taken out of another computer?

Why was the prior power supply replaced... was it because of similar problems of unexpected shutdowns etc?

Have you verified that all fans are spinning freely and that there are no wires in the way of fan blades? ( * This can cause a very fast shutdown if a fan is not spinning as the system will protect itself... I have seen people install power supplies and other devices and have wires in the path of fans that cause the fans to slow or not spin and it causes the system to shutdown like you have happening. )

[Jidt]

I took a look and it was a loose cable was in the way. I zip tied it secure and out of the way, and now everything is running smoothly. Thanks for the help!

[DaveLembke]

Glad to hear it was this simple