Random Red Cpu led lit

Jaiko

Reputable
Aug 5, 2015
4
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4,510
I am having some problems with a recent PC build, I could use some help :x
Yesterday I built a computer with the following specs : R9 290, Phenom II x6 1090t, Crosshair IV Extreme, 2x4GB 2400Mhz G.Skill TridentX, WD Velociraptor 300gb, Aerocool Strike Air X, Corsair ax760, Corsair h100i, Corsair m90, Corsair k60, AOC 22 Led.
Since my last build with this Hard drive was a p7p55d pro and a xeon x3470, I figured that I should have installed Windows again, but I didn't have to! I was glad I didn't need to lose time reinstalling something and losing all my installed programs, but anyway.
Happy, I let the PC downloading some stuff at night and went to sleep. When I woke up, the computer was still on but no image on the screen and no lights on the keyboard nor mouse, and the CPU red led was lit. After spending a bunch of time testing out, I found out that : The PSU is not faulty (tested with a generic PSU, same problem). It's not overheat, also not HDD/Windows problem (Clearly).
When I turn the PC on, sometimes it boots normally, but even then it suddenly stops working (same there : fans on, motherboard on, red cpu led on, no image, nor keyboard light). Sometimes It doesn't even post (it gets stuck at cpu led). Sometimes the red led keeps blinking and tries to post but it can't. I'm desperate to know what's the problem here.
I bought the mobo and the cpu from mercadolivre (it's like Ebay, but in Brazil), both are used and according to the sellers, were working fine (and they were working fine for hours yesterday. Now it can't keep upfor 10 minutes). The longer I wait to turn the PC on, the longer it can hold on windows, but eventually it will stop.
I also tested with one stick of RAM, switched the GPU from one Pci to another, booted without any USB/Sata, it still gets the same problem.
Also I cleared the CMOS 2 or 3 times (it's just getting the battery out, with the PC turned off, and wait for a minute, right?). When I was wandering in BIOS to see my CPU temps (41c idle) the red cpu led happened 2 or 3 times.

Also, my h100i is installed kinda poorly (I don't have the AMD bracket right now), but since it is not overheating (and I put a quality thermal paste on), that's not the problem, is it?

I have certain knowledge in computers, so feel free to use any terms and ask anything (but YES, i have checked my PSU cables, 4pin, 24pin, everything is correct), but please, help, I'm really desperate here.