Question Have to boot pc without gpu, switch off, replug gpu and then only can I boot with gpu

[Samitha__akalanka]

As said by the question, I have to switch on the PC without the gpu, keep it turned on for a min and then switch off the PC and plug the gpu to make the gpu work. I saw that some have had this problem and people suggested the pcie cable of the PSU. As I do not have a another PSU to test, is it okay if I try a molex to 6 pin adapter weather that will solve the problem?
Gpu - gtx 660
PSU - 500w Antec psu
Motherboard - msi g41m p26
CPU - Xeon e5430
Windows 10

Sorry English is not my first language.
Any help would be appreciated.

 

[Ralston18]

Do not start by swapping power connections around.

Because the problem is not known doing such swaps may end badly....

First ensure that the GPU is fully and firmly inserted into its' host PCIe slot.

Second, make sure that the existing power connections are fully and firmly in place.

Third, update your post to include full system hardware specs and OS.

What all else is installed in the PC?

 

[Samitha__akalanka]

I updated the post. Additionally I've installed two blue led fans and 500gb HDD.

 

[lynx1021]

Do you have your video in the bios set to PEG or PCI? Needs to be set for PEG or PCI Express, crappy manual doesn't show all the Bios settings. Probably under integrated peripherals , or advanced Bios features,

 

[Samitha__akalanka]

Do you have your video in the bios set to PEG or PCI? Needs to be set for PEG or PCI Express, crappy manual doesn't show all the Bios settings. Probably under integrated peripherals , or advanced Bios features,

It is set to pcie