My in-laws have a Dell Opti-Plex 166mhz pentium . They need to add more RAM but don't have a clue what type to get. I need to know what type and how many pin RAM to buy.Any help would be greatly appreciated. It probably has EDO 72-pin RAM. Only way to be sure is to open it up and pull out a stick or call Dell with the service tag number. Might also be on their website under the tag number. Later, Russell Smith Edtech Consultant, Journalist A+ Certified Technician http://www.rustysmith.com Visit our website regularly for FAQs, articles, how-to's, tech tips and much more http://nospin.com - http://nospin.org