I started working on pc's in the mid 90's I got so good at it whenever so,some from work had a problem with their pc's they'd bring it over to my place and I'd fix it for them. About a year ago I was bored with iPhone so I jail broke it, when I did that all hell broke lose. Immediately after someone had taken total control of iMac they hacked into every email account I had and on one of email accounts they deleted 10 years worth of email. They hacked into my Facebook account and took it over as well and even though I contacted Facebook and told them to delete the account because it had been hacked into they refused to,do it so I stopped using that account and created another one. The only thing all my emails accounts and my Facebook account had in common was my iMac. No matter what I did I couldn't get the malware off my iMac and because I wasn't familiar at disassembling an iMac I took it in to an apple repair shop and had them replace the hardrive but the kid that replaced the hard drive transferred everything off the old hard drive onto the new HD including the malware. I finally had enough and unplugged the iMac and put it in the closet and started using either my iPad or my Del laptop whenever I needed to get on a computer. I want to start using my iMac again but the malware is still on it my question is how do I completely format a hardrive that has Mavericks loaded on it? I know how to format the HD but Apple has a partition that's a read only and supposedly can't be removed but I'm almost positive that's where the malware is located and that's where my problem lies. Getting rid of that partition and reinstalling a fresh operating system one I load off a DVD not one that I download. Anyone got any advice on completely removing all partitions and creating a new master boot record?