Put the first line in the file.
Change it to \documentclass[CJK]{cctart} and save it as a tex file.
The ctx file is very old and has been eliminated.
Another method is to compile files directly under DOC without using an editor. I just can't do it all the time, which is inconvenient. )
Then your header file should be \documentstyle{cbook}, which can be changed to.
\documentclass[CJK]{cctbook} and save it as a tex file.
If you are not familiar with TeX, it is recommended to change a template. There are many university thesis templates available for download on CTeX forum:
/pub/cct/
Maybe you need to find the cctreport.cls file in your old computer.
But I still suggest you change the template. The template has a history of at least 10 years. Now that TeX has been improved a lot, the new template will only be more convenient.
If you still can't solve it, please post to CTeX forum to ask questions.