The Wii version is a faithful port of the original PC game. The graphics are not as good, but everything else works pretty much the same. The only real difference is the price, which is around $10 more for the Wii version than the PC version.
The Hardy Boys: The Hidden Theft tries hard to recreate the golden days of point-and-click adventure gaming. While its intentions are good, the exploration and puzzle-solving suffer from poor planning and execution.
Adventure games are about three things: exploration, dialog and puzzle-solving. The Hidden Theft only manages to successfully hit one of these points, and doesn't even soften the blow by giving us pretty things to look at.