I continue to see a lot of posts about wake-from-sleep issues with various HTPCs, usually experiencing a blank screen when attempting to wake an HDMI-connected HTPC.
I have the problem on my Assassin HTPC, and unfortunately it just seems like a largely-unfixable issue with EDID, HDMI connectors, hardware handshakes, A/V receivers, video card drivers, etc. I've tried all the various hacks, settings, workarounds, and voodoo, and even a hardware approach with Gefen's HDMI Detective, but nothing worked as a permanent solution for my setup.
I did discover awhile back, though, a simple and surefire (for me) way to wake the screen, without needing to force an annoying reboot that seems to be the only solution for many people:
When you experience a blank screen when trying to wake your HTPC, simply press: Windows key + P key, then hit Enter.
You may find that your display magically re-appears.
If you try this keyboard shortcut while your display is working, you can see what it's doing: Win+P invokes Windows built-in Projector setting, which you would normally use when connecting your PC to an external display, like a projector, and need to select how to split or mirror the display. Once the command has been invoked, the Enter key selects the first option, which is just to use your normal display instead of a projector, and you're immediately returned to your Desktop. Note that I've only tested this using Windows 7, so if you use another version of Windows, you'll need to see if there's an equivalent keyboard shortcut for it.
This essentially tricks your computer into refreshing its display output, which (at least for me) is all that is needed to bring the display back to life. I wish there were a more permanent solution to this problem for everyone, but until then, this little keyboard shortcut seems to be the most painless and reliably consistent way to wake my display.
Give it a shot.
And that can be programmed into a Harmony remote too.
There isn't (an equivalent keyboard shortcut for versions lower than Win7).
Multiscreen keyboard support is Win 7 feature.
You may be able to use something like AutoHotKey
to create a script to perform those key presses and then create a trigger event in task scheduler to run it when the PC comes out of standby.
Good tip although I have always done it using F8 or whichever key on the laptop. Recently I have been having trouble Remote Desktop'ing to my machine at work. I get a blank desktop but can see the Windows sidebar and start/task bar. If I click on a program, nothing happens. If I open the start menu, I can briefly see the background (with the apps) before it switches to the start menu.
I didn't have any trouble connecting to other machines. At work, I could use other machines to connect to my machine without trouble. I think the problem started happening when I connected a second monitor to my work computer. The machine is old (from 2007) using the AMD FirePro GL 3400 card. Both machines are running Windows 7. My home machine is an i5 using HD3000 graphics.
I think the bug is with the AMD card in my work computer. I was working around the issue by initiating shutdown and then immediately cancelling it. This seems to refresh the display but the drawback would be that a few of my apps would be killed before I could cancel the shutdown/restart.
When I saw this thread, I decided to try the Win+P combo the next time it happened and it worked. Cool. This will help until I get a new work machine next month.