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I am pretty sure you can but you wont want to for the following reason :

the ram you have is most likely ddr 2 ram and the ram in the other computer is DDR 3 it will work if you stick it it but then it will set the clock rate of the other ram in there to ddr 2 speeds meaning that your ram will be slower!
 
I am pretty sure you can but you wont want to for the following reason :

the ram you have is most likely ddr 2 ram and the ram in the other computer is DDR 3 it will work if you stick it it but then it will set the clock rate of the other ram in there to ddr 2 speeds meaning that your ram will be slower!

I second this...one is probably DDR3 much faster so don't do it.
 
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