Firefox/something else caused a complete system freeze, 'reset' switch taking ages to respond

[Rixxz2]

Hello people.

I assembled the system about three weeks ago, and up until this point it's been working perfectly.

Was just browsing the web, and clicked on an ad (which leads to an established Swedish PC-accessory reseller), which caused the entire system to freeze up completely. The monitor still received signals, but nothing was responding. I waited for about 30 seconds, but then I figured Firefox had completely fucked up somehow, and pressed the reset switch. Nothing happened at first, but after about 5 seconds, the system turned off completely rather than restarting.

I then pressed the power button, and it booted without any problems (Other than the "Windows wasn't turned off correctly bla bla" message).

I've now switched over to Chrome again, but considering it took ages for the motherboard to respond to my "reset" call, something tells me this wasn't due to a simple deadlock caused by poor coding, but due to some kind of hardware-level malfunction.

Specs:

i5 4690k (Not overclocked)

8GB (4x2) Corsair XMS 3

Gigabyte GA-Z97-HD3

GeForce GTX 770

Western Digital Caviar Blue 250GB

XFX 550W Pro

I've let Prime95 run it's "Blend" test for about two hours now, and so far no problems have occured.

Any ideas? Am I worried about nothing?

(gman003 I summon thee)

[alien_guy]

Could just be windows fucking up as it tends to do occasionally, not need to change browsers because of it.