Primary monitor goes blank after installing a secondary monitor

[chrischrischris]

So I recently installed a monitor (an old hp) into the same graphics card as the one i was using before. but after i boot up and get the orbs rotating, the screen (on my primary) goes blank. the hp monitor i added doesn't even know its attached to the pc and it goes to sleep. But, as soon as I unplug the hp everything goes to normal on my primary monitor. Can someone help? I want to use both monitors while gaming and stuff so yea.

System:
MOBO: MSI 870 G-45
GPU: His radeon HD 4870
CPU: AMD athalon II X3 440
PSU: antec 500w
HDD: WD Blue
SSD: OCZ 60gb (os)
Primary monitor: samsung syncMaster 2232Bw plus
Secondary: HP w2007

PS: my video card has two dvi ports. the samsung has an adapter that has like half the pins and the hp has an adapter with all the DVI pins on it. (is this maybe the problem?)

 

[officialexpert]

Check your GPU is supported for Dual Monitor or not?

 

[chrischrischris]

Check your GPU is supported for Dual Monitor or not?

probably because it has 2 outputs. or is this not the deciding factor?

 

[Markkk]

Make sure you have the Catalyst software installed so you can go into the advanced options and set your primary monitor to the one your want

 

[cst1992]

I don't use AMD, but even in NVIDIA, it boots up with one monitor only. You need to change the settings for using two monitors at once.

 

[Kekoh]

Windows automatically sets the second one up... he shouldn't have to do anything.

It sounds like you are using one DVI and one VGA, they do not mix well. I think the VGA monitor is just incompatible with your setup. DVI is a digital signal and VGA is analog.

 

[cst1992]

Windows automatically sets the second one up... he shouldn't have to do anything.

It sounds like you are using one DVI and one VGA, they do not mix well. I think the VGA monitor is just incompatible with your setup. DVI is a digital signal and VGA is analog.

Actually it's my VGA monitor and HDMI TV.
but I can use both just fine when I boot windows.