I have someone that asked me to upgrade thier memory, but if I can avoid it I don't want to open her case twice. Once to see what type of memory and once more to install it. It is a Pentium 2 with 32MB right now. I can use PC133 even if her other stick is PC100, right? it will just down speed to the lower 100Mhz, so basically the only thing I need to make sure is that it is 168pin memory, right? Do you think it would be anything else?