Question Red light and PC turned off

[Cryptikaia]

I have the case Aerocool Aero Duo one and i finished my build around 2 days ago, everything is running smoothly and good.

Yesterday i left the PC on and went for around 20-30 min to the grocery ( i have put power settings to not shut down after awhile like 2H) But the moment i came home i saw my screen go black from the hallway and then a moment later my pc went into (sleep mode) i would guess.. Pushed the power button and it came up with all programs there. But i noticed the lamp on the case was blinking red, i put my computer to sleep mode today and it was blue, so why was it red?

 

[hang-the-9]

Need to know what light exactly was blinking red? The power button light or something else? The manual to the case may be able to tell you.