Looking a way out to fix my problem with gpu and motherboard

[killingmachine12344856]

Hey, guys I'm in some serious trouble.It seems like my onboard GPU(Intel hd 2000) doesn't like my add on GPU(Radeon r7 250 2gb ddr3).For some reason the add on gpu shows blank screen on the monitor, but fans(both of heatsink and ADD ON GPU works).I noticed that the lights of keyboard and mouse glow once after switching on PC using radeon r7 and the monitor doesn't show up signal, more than that the pc remains idle and when i switch the power button off i switch off within no time. I have also tried few add on card like gt 710 zotac edition ddr3 2gb( which stucks up at BIOS screen). It seemed toe that the onboard GPU is having confilcts with the external ones. I tried to disable onboard gpu in the device manager but no luck, also on the BIOS(but can't find any options for the GPU or northbridge or southbridge configureations).My system:
CPU:Intel core i3 2100 3.1 ghz
GPU: intel hd 2000( onboard)
MOTHERBOARD:ECS H61H2M2 V2.0
SOCKET TYPE : LGA 1151
PSU: UNKNOWN 200W (also tried another PSU of 500w with the r7 plugged)no luck
BIOS: AMI v 4.6.2

THANKS

 

[Calvin7]

System Requirement for (Radeon r7 250 2gb ddr3) is a 400 Watt Power Supply.

System Requirement for gt 710 zotac edition ddr3 2gb is a 300 Watt Power Supply.

No-name generic power supplies are not recommended.

 

[killingmachine12344856]

System Requirement for (Radeon r7 250 2gb ddr3) is a 400 Watt Power Supply.

System Requirement for gt 710 zotac edition ddr3 2gb is a 300 Watt Power Supply.

No-name generic power supplies are not recommended.

 

[killingmachine12344856]

Hello, Calvin7 as you said about the POWER SUPPLY, I have already used 500W POWER SUPPLY to cheak. Infact i got the same error ( No signal ) on 500 PSU, with Radeon R7 plugged. Everything was normal with the onboard graphics, when using a 500W PSU.
The PSU was: Coolermaster 500W.

 

[killingmachine12344856]

System Requirement for (Radeon r7 250 2gb ddr3) is a 400 Watt Power Supply.

System Requirement for gt 710 zotac edition ddr3 2gb is a 300 Watt Power Supply.

No-name generic power supplies are not recommended.