upgraded, no signal to monitor!

[jonnybaxy]

I recently upgraded my desktops GPU, CPU, RAM and Mobo but now when I try turning it on I get a no signal message on my monitor...

GPU: Asus 1gb GeForce gt740 OC edition

CPU: AMD A6 6400K 3.9 GHZ

RAM: 2X4GB CORSAIR VALUE SELECT

Mobo: Gigabyte F2A88XM DS2

I've tried all the suggestions I've seen here,

Made sure I'm connected to GPU not onboard graphics, tested 2 different cables and 2 different monitors, reseated GPU + CPU

Also my old GPU doesn't seem to work anymore...

I also installed all these at once so as far as I'm concerned any one of them could be the problem

 

[popatim]

Did you disconnect power before installing these components?

 

[jonnybaxy]

Did you disconnect power before installing these components?

Yes I did,

Also I've just seen in my motherboard manual;
"To support PCI Express 3.0, you must install an FM2+ APU."

So do I need to get an FM2+ CPU?

Shouldn't the GPU run at 2.0 speeds instead?

 

[popatim]

yes it should work as is.
Make sure you have all the motherbd psu cables plugged in. there s 24pin and an 8 pin connectors, you need both.
Make sure the switch on the back of your psu is on or 1.

what happens when you turn it on?

 

[jonnybaxy]

yes it should work as is.
Make sure you have all the motherbd psu cables plugged in. there s 24pin and an 8 pin connectors, you need both.
Make sure the switch on the back of your psu is on or 1.

what happens when you turn it on?

I believe I may be using a 4-pin in the 8-pin slot, should that still work? because I read that it should as long as its in the closest holes to the CPU

Also it starts up, all the fans and interior is working, just no signal.

 

[jonnybaxy]

I've fixed it last night, I'd accidentally plugged a connector into the wrong pins in the MOBO,

But windows is no longer working, do I have to reinstall it?