Im trying to reinstall a nancy drew game that i

Try using another drive to install it, or remove all the registry entries and program files related to it (as long as losing your save points is okay) and re-installing.

If that fails, report back with the actual error message in detail, and make an image of the disk with Nero and install from a virtual drive, looking into any mis-steps it whinges about and attempting to clear the false tells it's tripping on.

best suggestion is to uninstall the game from Add-Remove Programs (in Control Panel) reboot your computer and reinstall. When you re-install one of the windows should tell you where it is being put (directory structure)... write it down and that will be your path. If all goes well then your game will work. If not then right click the icon to run the program and check the path to make sure it cooresponds to the one you took down during the installation. Make any changes necessary.

Oh and remember to delete all the shortcuts on your desktop and in the START->Programs area of your menu (after you do the uninstall) so that the fresh install puts new correct ones in there.