RAM upgrade


I had an older emachine running vista home on it that died so I gutted it for parts, drives and memory sticks. I was recently given a dell dimension 2400 running xp home that has 2x512mb memory, can I exchange the memory in the xp with the 1GB 1Rx8 PC2-6400u-666-12-ZZ memory from the emachine without any problems. I did a system check on the dell and it says it also has a empty slot on it and I removed 3 1GB sticks from the emachine could the 3rd stick also be installed on the dell?