Random shutdowns followed by boot loops

[bunny0143]

Hello,
About a week ago I received the components from my computer and my brother, who has a lot of experience building computers over the years and has built all his own, helped me put it together.
The first day or two the computer was running fine. After that, it started having random shut downs. The first few times it did it, the computer would completely shut down and then try to boot back up. The fans would start but the monitor wouldn't even get a chance to fully turn on before it shut down again. I turned off the power supply and waited an hour, it worked for the rest of the night.
The next day, the same thing happened. This time I tried to let the computer boot on it's own and it could not. After a few loops, each lasting less time then the ones prior, the attempted boot ups lasted a fraction of a second before turning itself off and attempting a restart, I am unsure if the hard drive even had a chance to start rotating. I once again turned off the power supply and left it to sit. About an hour later when I came back, it still wouldn't boot. I had to leave it overnight.
Next day it lasted almost the entire day. After reading some forums and the screen turning various shades of the rainbow a few times, I figured it may be the RAM. Had to purchase new RAM and installed it today. Computer ran fine for about 4 hours straight. Then it shut down and booted up without prompting for Windows repair or starting Windows normally.
Now we've been fighting with it all night. The computer has gone through multiple stages of shutting itself down, sometimes turning back on, and sometimes attempting to turn on but shutting right back down. So far, we have tried replacing the RAM, shutting down the power supply, tried setting BIOS to all default settings. Core temp reads that everything is coming out either below normal or normal even when the computer is pushed to 100%(Prime95). The average temp is about 35-40C. Below is a list of what is in this computer.

GIGABYTE GA-Z68XP-UD3 LGA 1155 Intel Z68 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard

COOLER MASTER Storm Sniper SGC-6000-KXN1-GP Black Steel, ABS Plastic, Mesh bezel ATX Mid Tower Computer Case

CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model
CMZ8GX3M2A1600C9

GIGABYTE GV-N570OC-13I Rev2.0 GeForce GTX 570 (Fermi) 1280MB 320-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card

Intel Core i5-2500K Sandy Bridge 3.3GHz (3.7GHz Turbo Boost) LGA 1155 95W Quad-Core Desktop Processor Intel HD Graphics 3000 BX80623I52500K

LITE-ON DVD Burner - Bulk 24X DVD+R 8X DVD+RW 12X DVD+R DL 24X DVD-R 6X DVD-RW 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM Black SATA Model iHAS124-04 - OEM

CORSAIR Enthusiast Series TX750 V2 750W ATX12V v2.31/ EPS12V v2.92 80 PLUS BRONZE Certified Active PFC High Performance Power Supply

Western Digital 1.5 TB Caviar Black SATA 6 Gb/s 7200 RPM 64 MB Cache Bulk/OEM Desktop Hard Drive - WD1502FAEX

Cooler Master Hyper 212 Plus 120mm Sleeve CPU Cooler, RR-B10-212P-G1

 

[Raiddinn]

Sounds like your PSU is not working.

This type of thing often happens with bad PSUs or bad RAM. If it was bad RAM, I don't think it would work fine for a whole day and then start having the problems again.

Ask the brother if you can borrow his PSU.

 

[bunny0143]

Trying PSU later tonight. Unplugged and reinserted CMOS/BIOS battery and have not had problems since. Is there a chance that it is my motherboard?

Edit: Computer once again only lasted about 2-3 hours before crashing.

 

[Raiddinn]

For any given problem there is some chance that it is because of a bad motherboard. For some problems the chance is as low as 0.01%. For some problems the chance is like 99%.

I asked you to check two things that weren't the motherboard, because they are both much more likely to be the cause than the motherboard is likely to be the cause.

 

[furry_roadkill]

It also sounds like a psu issue to me. Sometimes a bad psu will overheat and shutting them down for a while allows them to cool off. Did u check to make sure the psu has good ventilation and the fan is spinning on it?

 

[bunny0143]

The fans are all doing well, and I have amazing ventilation on this system. Everything remains nice and cool. RAM has been replaced already and did not fix the problem. Replacement PSU will be here in a few days so I can try that. Thanks for the help, I'll let you know how it goes.