Install Mac OSX on a new replacement hard drive We have an iMac in our office which we are going to put an SSD in (The iMac itself is past warranty and apart from the slow hard drive is functioning fine) however no-one of us in the IT Department are used to using Mac and we can't seem to work out how to re-install Mac OSX on a new hard drive as we can't seem to get a .iso file for MacOSX like you would with Windows

How would you re-install Mac OSX on a replacement Hard Drive
You need a USB stick with an OSX Installer loaded onto it.

Before you remove the old hard drive you need to prepare the USB stick so you can install it on the new drive.

Check out the Apple walk-through here.

After installing the OS you can restore your old files from a time machine backup.

The restore partition on the old hard drive could work but you need an enclosure or sled to connect the old drive externally.

Good luck!