So i've decided to buy an iMac on Monday or Tuesday, whichever day the new ones come out on. Anyways, My dad has agreed to help out as its replacing the old family PC (viruses and monitor is dying). So my problem is that my sister wants to use this new computer as well. I've asked her to help and she has said no. It wouldn't be so much of a problem if I could just straight up buy it, but I can't Its a need it really soon basis. Should i set up the users with passwords so she can't use it. It seems harsh to me but I already pay for the internet and the wireless router that our family uses, My mom has a laptop so she doesn't want to help (plus she doesn't like mac). It only seems fair that she helps out if she wants to use it for her Elementary School projects... kidding, she's 22. and she works. any advice would be good.