I have a late 2009 i7 quad core iMac w/12 gig of RAM. I have a minor problem with the LCD and am considering getting it replaced. At the same time I figured I would either have the 2TB HDD or the Super Drive replaced with an SSD. I have a lot of personal data on my machine and don't feel comfortable just handing the machine with all of my data and emails over to someone else, despite the fact that I generally trust that the shop is honest. I am wondering how best to secure the data when bringing the computer to the shop for the repairs, upgrades, figuring that I would have to provide my password in order for them to be able to test the machine and do the work.