New PSU, PC won't turn on

My sister just got a new PSU for her PC, I put it in, when on the motherboard has a slow blinking green light and nothing else, the CPU's fan doesn't even rev or anything.

PSU is a Corsair VS550, motherboard is an ASUS H81-PLUS. There is one different compared to the previous PSU though which I don't know if it's an issue or not? The CPU plug on the motherboard if a 4 pin labeled as EPU, whereas this new PSU only has an 8 pin CPU plug.

I know it's just two of the four pins connected together, but just mentioning it in case it's relevant.

Does the PSU have a single 4 pin plug at all? If not you may need that.

You could try the other side of the PSU's 8 pin connector.

Did you plug in the 24 pin MOBO connector?

Detach the four-pin connector from the 8-pin cable, and then plug that four-pin cable directly into the motherboard ATX12V.

Just realised that could happen, tried it, same thing. Just the blinking green light.

The ASUS H81-PLUS requires a PSU that complies with ATX 12V specification 2.0 (or later). The VS550 complies with that.

I would check your connectors again, or put the old power supply back in and see if that works.

Ranger4 said:

This YouTube video might help you with those connectors.

Corsair VS550 power supply review, unboxing how many connectors, cables and stress test - YouTube

I'm having the same problem and will test the PSU next. I left the PC to update and proceed on installing the new brake kit and fuel wheels on the truck. When I return back the PC is off and can't power on so I changed up the extra Corsair PSU. Gonna try those tests and see if the PSU will work.