OK, so I tried to mess around with the app_info.xml file for my P4 and GTX280. This is what I tried to run:
Code:
<app_info>
<app>
<name>hcc1</name>
<user_friendly_name>Help Conquer Cancer</user_friendly_name>
</app>
<file_info>
<name>wcg_hcc1_img_7.05_windows_intelx86__nvidia_hcc1</name>
<executable/>
</file_info>
<file_info>
<name>hcckernel.cl.7.05</name>
<executable/>
</file_info>
<app_version>
<app_name>hcc1</app_name>
<version_num>705</version_num>
<platform>windows_intelx86</platform>
<plan_class>nvidia_hcc1</plan_class>
<avg_ncpus>1.0</avg_ncpus>
<max_ncpus>1.0</max_ncpus>
<coproc>
<type>[COLOR="Red"]nvidia[/COLOR]</type>
<count>.5</count>
</coproc>
<file_ref>
<file_name>wcg_hcc1_img_7.05_windows_intelx86__nvidia_hcc1</file_name>
<main_program/>
</file_ref>
<file_ref>
<file_name>hcckernel.cl.7.05</file_name>
<open_name>hcckernel.cl</open_name>
</file_ref>
</app_version>
</app_info>
All I got were "GPU missing" errors in the event log.

Any thoughts on what I might be missing?
EDIT: Nevermind - I looked at the first post again and saw that the co-processor type should be "Cuda" and not "nvidia." I'm going to give it another go now...