I can find viewers for the file format, but nothing for conversion as such. That's the problem with proprietary file formats, they want licensing or royalties, and that in return tends to mean no free tools. I tried it in Keyshot v3 and that couldn't work with it either. But generally speaking you need to have the sldprt files to go with the assembly, you then put all the parts and the assembly file all in the same folder and then it should import into whatever software you are using that can read solid-works.

HTH

Martin Spencer-Ford