First, I've had a dual monitor setup with two Asus VH238H 23" monitors for a couple years now. Until the last month they've worked flawlessly. The first is connected to an AMD Radeon HD 6570 card (Sapphire brand, I think) via an HDMI cable, the second to the same card with a DVI cable. The DVI is the one I'm abruptly having trouble with:
If I put the computer to sleep or just switch the monitors off for a time while I'm out of the office, when I bring everything back to life the 2nd (DVI) monitor remains blank, while the power indicator blinks on & off. Sometimes it abruptly turns on after a few minutes, sometimes it just blinks & blinks until I switch the system entirely off & then reboot. (A simple restart doesn't always correct the problem.) When it's on it works flawlessly, but getting it to come back on is a pain.
I've tried switching the cables to attach #2 via HDMI & #1 via DVI, but the same monitor does the same thing, so I'm deducing the problem isn't with the cable. Likewise, I can unplug the monitor for some length of time then plug it back in, but the problem
continues. I originally thought the monitor might be dying, but that would seem to suggest the problem is with the signal coming from the computer.
This is a custom-built computer with an AMD A8-3580 APU on a Gigabyte GA-A75-UD4H motherboard, with 16 megs Corsair Vengeance memory (4x4), using 64-bit Windows 10 Pro.
I have updated to the latest display software/drivers offered by AMD. As I've noticed several others with a similar problem, I'm tentatively concluding this is a software issue with one of the mystery Win 10 updates, since shutting down altogether then starting up fresh alleviates the issue - until the computer goes to sleep again. I can't find any troubleshooting technique, software switch or registry item that might deal with it on a more permanent basis.