This is the safest bet. Many users have uploaded ISO images (disc copies) of the original CD-ROMs. You can search their "Software" library for "Nickelodeon Jigsaw."
A long-standing repository for retro PC titles. They often host the files, though they may require a small fee for high-speed downloads or offer a slow free version. nickelodeon-jigsaw-pc-game-free-download-full-version
For the most authentic (and functional) experience, some enthusiasts run these older games using VirtualBox with a Windows XP installation. Important Safety Warning This is the safest bet
Be cautious of sites claiming to offer "Free Full Version Downloads" that require you to click through multiple suspicious pop-up ads or download custom "installers." These often contain malware. Stick to the or MyAbandonware for the safest experience. nickelodeon-jigsaw-pc-game-free-download-full-version