To make sure you get the right one, look at the memory standard your motherboard supports: If it says something like DDR3 1333 or DDR3 1600, just buy memory with that same value and you should be fine.
How long after being exposed to the stomach flu until symptoms show? typically it is between 24-46 hours (most often starts after 36 hours) but can be aslong as 72 hours.
That's the incubation period. For the flu, it is about two to five days. So if you are exposed today, you probably won't have any symptoms for three to five days. Then you have a little headache, maybe a few aches and pains and maybe a low fever. Then, the next day, you have a high fever and a runny nose.