At first, Boinc would run fine for many hours before the "GPU Missing". Then it started happing every few hours, then very frequently.
Sometimes it would fix itself, and would start working again, but not any more.
Ive seen it toggle back and forth between running and gpu missing, then back to running.
now it's happening all the time, even after a reboot.

Windows 7 x64
Boinc 7.4.42 x64
Radeon HD 7870s
AMD Driver: 13.251.0.0

Show us the startup logs, and the logs of when it happens.

Claggy

Can you tell me where to find these logs? All I can do currently is get a screen shot of the GIU.

From the Event Log, Shortcut to open it is 'Ctrl+Shift+E'

Claggy

Copy and Paste, Not truncated screen shots please, that's what the Copy buttons at the bottom are for.

Oh, and Don't use Remote Desktop, that uses different drivers that don't have Cuda and OpenCL support, use a different method of accessing the host.

Claggy

The copy/paste doesn't work accross RDP for some reason. The box is in the back of my garage and doesn't have any console attached, so RDP is the only access I have.

You've answered your own question. The GPU will go missing every time you use RDP.

You'll have to use an alternative to remote desktop:

http://en.wikipedia.org/wiki/Comparison_of_remote_desktop_software

I can't remember which one's are often used by Boinc users.

Claggy

That seems to have fixed the issue. The GPU's are running again, as long as I don't login in with windows RDP.

I can't remember which one's are often used by Boinc users.

One of the free variants of VNC, I think. I was recommended to try TightVNC.

http://sourceforge.net/projects/vnc-tight/

I use Team Viewer most of the time.

I have also been able to use: UltraVNC, LogMeIn, and PCAnywhere.

---

I ended-up using Chrome RDP, which seems to work fine.