Betinho:
The correct phrase in English (if you are still curious) is "the computer hangs" or "the computer fails to respond" but crashes gets the point across just fine.
Two questions:
Do you receive any error messages? (if you do, then try to reproduce the problem and write the exact message down, then let us know what it says).
Have you checked the Web site of the maker of the Clipper program for a software patch to fix the problem that you may download and install? (if the site still exists, and this was a common problem with Windows 98 SE, they probably have the patch available).
Regards,
Doc