First of all let me say that I am not a Mac person. I am very familiar with a PC. I have a an iMac8 which belongs to my mother running Os X 10.6.8. I have the original gray install discs ( Mac OS X 10.5.2 ) that came with it. It also has Microsoft Office Suite 2011 and Adobe Creative Suite 8 installed of which I have both programs. The only thing I care about in CS is Photoshop. It has Deep Freeze installed. Some years ago she allowed a college student to work on it to clean it up because it was running slowly. Not only did this student wipe the drive he also kept the external drive that our back up was on. This tech locked Deep Freeze ( 2 GB space ) so no one is able to look to see whats in it. Preferences tells me that the System is the owner. I'm not able to save anything new. If I shut down everything is gone when I start it back up. I need to get rid of Deep Freeze completely (don't need it) and reinstall OS x.
I know that I am able to upgrade this as far as El Capitan. Problem is Im confused about exactly which updates to apply first. Unsure if the Combo updates are all I need. There are so many of them it's mind boggling to me. I also would like to know if I can download them to a USB drive and install them from it.
I plan on upgrading the ram to 4 GB currently at 2 GB. I also would like to know if I could use my 1 TB My Passport USB drive to back it up with Time Machine. I know this is a lot to ask but I really could use the help.