No, short of removing the hard drive, then erasing or destroying it.
If the computer is named a "PowerBook", it would be a 68K-based or PowerPC-based Mac. The first PowerBook came out in October 1991, and Apple discontinued the last one in April 2006. Depending on the model, and the type of internal drive it uses, you might not find it easy to get an external enclosure to even try using its internal drive as an external drive for another computer.
Another issue (if you're hoping to recover the data, not just erase it) is that an old hard drive might be formatted using HFS (no "+"). Modern Macs support HFS+, but not the original (no "+") version.