If you only need to view SLDPRT files, copy the swViewer.exe and its associated DLLs from an installed copy of SolidWorks 2004. The SolidWorks Viewer (eDrawings 2004) is genuinely portable. You can place it on a USB stick and open legacy drawings without installation.
While the concept of "SolidWorks 2004 Portable" appeals to nostalgia or the need to access legacy data without a complex installation, it is not a viable professional solution. Portable Solidworks 2004
Technically, it requires unstable hacks to bypass deep registry and driver integrations. Legally, it is a violation of intellectual property rights. Operationally, it presents a high risk of data corruption and security compromise. If you only need to view SLDPRT files, copy the swViewer
Recommendation: Organizations needing to access 2004-era SolidWorks files should utilize a legitimate legacy license within a Virtual Machine (VM) running Windows XP, or subscribe to current SolidWorks versions which have robust backward compatibility features, rather than resorting to unauthorized portable distributions. SolidWorks 2004 was designed for Windows XP
SolidWorks 2004 was designed for Windows XP. Unlike modern portable applications that store settings in .ini or .xml files, SolidWorks 2004 relies heavily on the Windows Registry. It writes thousands of keys to HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER regarding:
For a portable version to function, a "launcher" must usually emulate or inject these registry keys into the host system at runtime and remove them upon exit. This is technically complex and unstable.