Strange shutting down issue

It's a strange problem. When I fire up the system it starts and then anytime between the BIOS check and the Windows login, it voluntarily powers down. When that happens in that span varies. It also takes a long time to detect the HDD arrays. But if I wait a day or so. I can fire it up no problem. It lasts a few days, then powers down again.

It's acting as if something is overheating, but I'm sure what. I selected motherboard due to the timing of the issue, but I could be power supply, memory, or even HDDs. Any help tracking down the culprit is appreciated.

What are your system specifications?

can you provide the model #'s as well? especially for the PSU. In the mean time. try going into bios and see what your temps are after a few minutes, just to be safe. I ran into a similar problem and the cpu was overheating.

OK so temps aren't an issue, good. At least the one you have has active PFC and is 80+. I would try another PSU to see if it fixes it. I'm not sure how long you've had it, but yours may be starting to wear out. Get it somewhere locally so you can return it, fry's for example. if that's not your problem. Other than that. have you made any changes to bios or disconnected/reconnected anything? just a thought.

It's possible. A PSU that's going can cause all sorts of havoc within a system as it's not providing a constant and steady power flow. Kinda like having bad gas in your car.