Nancy.drew.secrets.can.kill.zip ... — File:

: Instead of the default Program Files (x86) path, create a new folder directly on your C: drive or in Documents (e.g., C:\Games\NancyDrewSCK ) to avoid permission issues.

If you're stuck on the main puzzles, GameFAQs and Mystery Manor provide detailed solutions:

: Move all files from the CD Video folders of both discs into the installed game’s HD Video folder.