Endpoint installation on thin client with limited space

Hi,

Trying to install endpoint onto thin clients with Windows 7 embedded OS.  We're restricted with space so tried the approach using a USB key for temp files as suggested in a different thread (albeit for XP, not Windows 7).  It seems to run through the installation ok and looks to complete but the program cannot be found on the thin client afterwards.  No error message given during the installation.

Any ideas?