If you have a dell latitude C series laptop, there's a slide panel on the bottom, that opens up, then you insert the RAM, you'd need an EDO 144 pin SO-DIMM for the lattitude CP, or a PC66 or higher SDRAM 144 pin SO-DIMM for a CPi. I'm not sure about the other models, but if you have the manual, you can almost definately find out what type of memory it takes, and how to install it, if you don't have the manual, check dell's support web site for that info.