I would take a pretty safe bet that you would get away with a Stick of PC133 SDRAM, it's the most common type as it wil lwork weather your machine is using PC100 or PC66, it's backwards compatible and it's unlickly your machine is using registerd ECC Dimms or anything like that.
Most helpful piece of infomation would be, What Motherboard do you have, if you can't answer that then what kind of processor do you have?
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Hesperex Freth: 1st son of Matron Mother Shi'nayne Freth, 1st house of Ched'Nesad. Weapon master and patron of house Freth.