If it's from 2000 and they were created using WinZip up to v8.0, you can use the Passware Kit and the SureZip recovery as per http://www.lostpassword.com/attacks.htm#surezip

> SureZip attack decrypts Zip archives created with WinZip version 8.0 and earlier in less than an hour regardless of password used to protect it. At least 5 simultaneously encrypted files are required in order to process the archive. Archives created with WinZip are supported.

I used this when it first came out and even with a 60-char password, if there were more than 5 files it could extract them within an hour (sometimes less than 5 minutes).