I am using Windows 7 Ultimate x64, with all latest SPs and updates.

Have been using BOINC/GridRepublic x86 v5.10.30. The program stopped processing new work, and as near as I can tell indicated that a newer version of the client was needed.

I've attempted to install the latest client, v7.6.33 x64, with and without VirtualBox. The VB portion will install fine, however the actual client errors out part way through installation stating it cannot find "GridRepublic.msi", and seems to be using the randomized temp folder the installer created as its source. I've done a search for this file on my PC and it doesn't exist. I've also not been able to locate a copy on the internet.

Neither the existing install or new attempted install are set to be a service.

Thank you for any assistance.

When a problem mentions msi, then this is a good place to start:
Windows Installer Error 1706: Setup cannot find the required files / 1714: older version cannot be removed / BOINC.msi cannot be found / The feature you are trying to use is on a network resource that is unavailable / Error 1325. is not a valid short name