Joulescopes should not need any special driver installation. The Joulescope software uses WinUSB as the OS driver, and WinUSB is supposed to be included with Windows 7. What I call the Joulescope driver is really python code (with some Cython compiled into native machine code) running in user space that communicates with the Joulescope device using WinUSB. Windows 7 should know that the attached Joulescope is supposed to use the WinUSB driver through special USB descriptors that each Joulescope provides to Windows.
However, I did have another report of an issue on Windows 7 where “Joulescope” showed up under “Other devices” in Device Manager with the yellow exclamation point. Is this also what you are seeing?