Hello,
I just installed 4G ram on my Acer Apire one 522 netbook with windows7 starter, it looks like it can only use 2G, is there any way I can make full use of all 4G?
The only way for you use all 4G is to upgrade Windows (assuming you don't want Linux). The cheapest option for you will be to buy windows 8 upgrade which costs $40.
It also shows that you can only put in a max of 2gb in a slot, and the unit has only one slot, so thus you are limited to one 2-gb chip. Not sure what you stuck in there though.