The instructions are really only for administrators in enterprise settings. Mucking with your registry without an understanding of the risks is not recommended. However, search for the preference here: Preference Reference for Acrobat and Adobe Reader.
Additional deployment and config information is here: Introduction — Enterprise Administration Guide. Refer the the preferences chapter as well as other sections.
Note 2 things:
- The preferences are not often there by default. You have to create them manually.
- You can only change the setting on machines you control.
hth,
Ben