BOINC 6.12.34 ok in Windows 8 Dev Preview

[AMDave]

Hi there, ertank. Welcome to the AMD Users forum.
from my first post in this thread:

... select Advanced settings during the setup and select the 'use unprivileged account' check box.

Make sure you install the right client and GPU drivers for your architecture, x86 (32-bit) or x86_64 (64-bit) - don't mix.
If you have trouble with 64-bit, then remove the driver and the client, then install the 32-bit versions of GPU drivers and BOINC client.
If the BOINC client does not detect the GPU driver, then you may have to try a different version of the driver.

I did not run GPU in the Windows 8 dev preview.
There are no guarantees, it is the DEV version after all.

Older versions of the BOINC client may not work, newer versions of the BOINC client are still in development and may not work.
But that version should get you up and running
As Dirk Broer suggests, I did not run the BOINC client as a service in Windows 8 Dev Prev.
The BOINC client installer does not yet support Windows 8, but I believe they are working on it in the new versions under development.