My second monitor works on boot up but then turns black!

Hi there I recently upgraded to have two monitors for my pc.

My graphics card is the AMD radeon hd 7770 and I have a Benq GL2250 and a Samsung S22B150.

On first setup everything was fine with my first monitor (Benq) plugged in via vga from the monitor into a vga to which I think is a dvi-i adapter and then into the graphics card. My second monitor (Samsung) which was through a vga coming from the monitor into the graphics card via a vga to hdmi adapter.

Everything was fine for about a month but the computer went into sleep mode last night and when i got home from work this morning the second monitor wasn't working and "Check signal cable" was jumping around the screen. I've tried swapping the vga's from both monitors with both adapters. Whichever monitor is plugged into the vga to HDMI converter is the on that won't work properly whereas the other monitor is fine. The monitor that is connected to the HDMI converter will now cut on and off randomly with my second screen showing on it (more off than on) and I've tried moving the resolution down from 1920x1080 to 1600x900 and the second monitor works fine, until i try to play a video or some type of media which promts the monitor to keep cutting out rapidly.

The vga to hdmi converter used to accept 1920x1080 resolution and worked fine but now if i change it to that the screen stays black and it says check signal cable, im just wondering what i could do to change it back or am i stuck with 1600x900? and if i am what caused it to work before?

Any help is appreciated.

Thanks.

sorry for the late reply RWARD18888, It sounds to me like the setup with the adapter is causing a problem with DHCP, for your screen to display certain content, it needs to do a digital handshake, if the VGA is being used then the handshake isn't going to happen (VGA is analog), since you're using a digital and analog signal at the same time, the digital will always take priority over the VGA, so it's only displaying on the other screen, as for the screen cutting out, it maybe a fault with the adapter itself or cabling, have you got a HDMi to DVI cable? you can then use the DVI adapter for the samsung monitor then.