I really hope someone can help me. (Multi-display issue)

So my graphics card is an ATI Radeon 6770. I had two HP 2511x 25' LED Monitors hooked up for the longest time, and it was great, no issues whatsoever. Then I went and bought a 3rd monitor and this is when the frustration started.

I am using windows 7 (64 bit)

I purchased an Accell UltraAV active Display Port adapter and an additional HP 2511x monitor.

It worked great, it worked for about 2 weeks, then the 3rd monitor hooked up to the display port, kept going into sleep mode. The PC still detected it, I could drag windows onto it, (without seeing them of course) and when I did the 'detect monitors' it says that it finds it, when it says 'identify monitor's it of course shows me 2 and 3 but not 1.

I tried everything, updating drives, uninstalling the monitor, re-installing, disabling, enabling, nothing.

I swapped out the DisplayPort adapter, no change. I swapped out the monitor for another, and it worked! Thank god I thought, found the problem. Now this evening, after turning my PC back on.. I am right back to where I started again.

I have basically swapped out everything I could already. This damn monitor keeps going into sleep mode and I have no idea what I can do to fix it.

Has anyone experienced this issue before? Are there any suggestions? I am at my wits end at this point, and returning everything again isnt an option.

I would love any assistance that can be provided by you guru's.

Thanks very much!

Some monitors with multiple input ports will properly autoselect the connected one. Others need a manual selection of the proper input port.
Without the proper input port selection, I would expect your symptoms.

First have you installed the monitors newest driver? people forget that and just do the GPU sometimes.
http://h10025.www1.hp.com/ewfrf/wc [...] 76902#N152

If you are using any form of power saving, sleep, suspend, or hibernate disable them. set the monitors to turn off never. Then see if it continues.

Did you swap DVI cables at anypoint of keep using the same when you swapped monitors around, and are you running at the native Res/refresh rate?

The problem is most likely your adapter (even though you tried another, I'm assuming you tried the same style with the USB plug for power). You're using the older style Adapters that were necessary when Eyefinity first came out. I had this same adapter and noticed around the time of the release of the "Officially" supported adapters I started having trouble with my adapter. My adapter wouldnt work properly with any driver after Catalyst 11.4. Any driver after 11.4 and I had issues simliar to yours. The monitor would be detected but either nothing would show up, or I couldnt set the correct resolution on it. As soon as I got one of the newer Adapters that AMD officially supports things started working fine again. Heres the adapter I switched to.

http://www.newegg.com/Product/Prod [...] 6814999031