The header files have control scripts used in WinSPICE (actually Nutmeg) that should be removed when using HSPICE. The scripts start with .control and end with .endc LasiCkt generates netlists that end have a .cir extension. HSPICE likes to see (at least PC versions) files that end with .sp A trick to save the files without a gratuitous .txt being tacked on the end of the filename is to put the file name in quotes. That is, in wordpad or notepad save the file as "mycircuit.sp" and it won't add a .txt to the end.