To find out info about your system,
Click on the Apple symbol in the upper left of the OS X main menu bar. A drop down menu appears.
Click About this Mac. A smaller popup window appears. This gives you basic info like what version of OS X your iMac is running, the speed of your iMac's CPU and how much RAM is installed.
Click on the button that says More Info. A larger window appears giving you a complete overview of your iMac's hardware specs.
Highlight all of this info and copy/paste all of this into another reply to this post, editing out your iMac's serial number before actually posting the reply.
This will tell us everything about your iMac so we may begin to help with your iMac issues.
In the meantime.
To install Snow Leopard for the first time, you must have a Mac with:
- An Intel processor
- An internal or external DVD drive, or DVD or CD Sharing
- At least 1 GB of RAM (additional RAM is recommended)
- A built-in display or a display connected to an Apple-supplied video card supported by your computer
- At least 5 GB of disk space available, or 7 GB of disk space if you install the developer tools
OS X 10.7 Lion system requirements
To use Lion, make sure your computer has the following:
- An Intel Core 2 Duo, Core i3, Core i5, Core i7, or Xeon processor
- Mac OS X v10.6.6 or later to install via the Mac App Store (v10.6.8 recommended); you can install without Mac OS X v10.6 by using an OS X Lion USB Thumb Drive, available on the Apple Online Store
- 7 GB of available disk space
- 2 GB of RAM
OS X 10.8 Mountain Lion and OS X 10.9 Mavericks system requirements
To install Mountain Lion or Mavericks, you need one of these Macs:
- iMac (Mid 2007 or newer)
- MacBook (Late 2008 Aluminum, or Early 2009 or newer)
- MacBook Pro (Mid/Late 2007 or newer)
- MacBook Air (Late 2008 or newer)
- Mac mini (Early 2009 or newer)
- Mac Pro (Early 2008 or newer)
- Xserve (Early 2009)
Your Mac needs:
- OS X v10.6.8 or OS X Lion already installed
- 2 GB or more of memory
- 8 GB or more of available space