Desktop Computer Not Booting - Issue Appears to Be CPU or Motherboard.

Hello, I put together a computer about 5 years ago for the family and it appears to have died.

The specifications:

• Intel Core i3-4130 Haswell Dual-Core 3.4 GHz LGA 1150 54W

• ASUS B85M-E/CSM LGA 1150 Intel B85 HDMI SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard

• Team Vulcan 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory

• Rosewill RD700 – Stallion Series 700-Watt Power Supply

• EVGA 01G-P3-1460-K1 GeForce GTX 560

• Windows 10

I tried isolating each part and removing the CMOS battery, but attempts to boot would at best result in a short burst of light on the power buttons the cases fans moving marginally.

Since I was unable to get any response from booting, even when every component besides the CPU was removed I ordered a new PSU & and PSU tester.

PSU tester
EVGA 500 W1, 80+ WHITE 500W

I tried again with the new PSU and again I was unable to get the computer to show signs of booting. At most it would still be a short blue/red burst from the power button on the case and the case fans moving marginally. I also tried shorting the power pins on the motherboard to rule out case button being the issue, I didn't see any result but I'm not sure if I did it properly.

I tested the new PSU with the PSU tester and it appears to be working. I was able to get the case fans and the optical drives to open when I had things connected to the PSU tester, so I'm relatively certain that the new PSU is good.

Now I'm trying to figure out how to go about proceeding. I don't have another LGA 1150 motherboard or CPU to attempt to test those components. Replacing the motherboard or CPU individually is not guaranteed to fix the computer and restricts me to using the LGA 1150 socket. In the case of buying the motherboard/cpu first and the issue not being resolved and then having the buy the other component I think I would end up spending more than getting some sort of combo.

The computer is mostly used by my parents. One of them just bought a laptop, so if the desktop were fixed it would primarily be used for web browsing, email, bills, viewing pictures, etc.

Any suggestions on figuring ruling out CPU or motherboard, or how/what to replace them with?