hayley...if i can call u that, it should depending o how many slots u have. ur system if it is this one:
http://cgi.ebay.com/ACER-Aspire-5100...03230829a13315
the system can support upto 4gb of ram. that meaning if u got 2 slots, yea that means 2gb per a slot.
any q's?
ok my bad, i just scrolled down this guys ebay page, u should go by with what pceye said.