I was just given a mac pro A1289....help please with install

A1289 identifies it as one of a dozen models from 2009 and later. Exactly which is it by processor speed or MacPro 4,1 designator or anything else you know?

Here is the problem: Many of the Mac Pros later than the 2009 model can run 10.6.8.

The last Full Retail DVD contained 10.6.3, which will not install on 2010 or later.

my 2008 Mac Pro is running Mavericks. So I assume yours can too.

All Mac Pro models can run Snow Leopard. The only exception is the brand new "Late 2013" that starting being sold in late December. So that is no problem.

Upper right Apple icon, About This Mac:

Mac OS X

Version 10.x.x

Processor (2.66) okay that surely sounds like Early 2009 4,1

memory: xxGB xxxMHz etc tells you what type of memory, tells us more about mac model

"More info..."

Here you find hardware profile of what it is, what is installed, processor, gpu, ram, disk drives and more

Mac OS X Help

http://www.apple.com/support/macbasics/

Isolating Issues in Mac OS

http://support.apple.com/kb/TS1388

https://www.apple.com/support/osx/

https://www.apple.com/support/quickassist/

http://www.apple.com/support/mac101/help/

http://www.apple.com/support/mac101/tour/

Get Help with your Product

http://docs.info.apple.com/article.html?artnum=304725

Apple Mac App Store

https://discussions.apple.com/community/mac_app_store/using_mac_apple_store

How to Buy Mac OS X Mountain Lion/Lion

http://www.apple.com/osx/how-to-upgrade/

TimeMachine 101

https://support.apple.com/kb/HT1427

http://www.apple.com/support/timemachine

Mac OS X Community

https://discussions.apple.com/community/mac_os

Recovery Mode

http://support.apple.com/kb/HT4718

ExpressLane

https://expresslane.apple.com/

Startup Manager: How to select a startup volume

http://support.apple.com/kb/HT131

iTunes Store, App Store, iBooks Store, and Mac App Store account When you use Apple services, such as the Apple Online Store or registering your product online, you create an Apple ID. You can use the same Apple ID for iTunes, the Mac App Store, iCloud, iMessage, FaceTime, Game Center, and more.

It is recommended to use only one Apple ID.

If you have registered your product or used any Apple services, you should followthis article to use an existing Apple ID with the iTunes Store or Mac App Store.

http://support.apple.com/kb/HT2534

To configure a Mac Pro to work with Aperture, Lightroom, Final Cut, or Photoshop, get to know the hardware and how to optimize RAM, disk drives (SSDs) and more:

http://www.macperformanceguide.com

A1289 and 2.66 speed will be a 2009 4,1 if it has four cores:

http://www.everymac.com/systems/apple/mac_pro/specs/mac-pro-quad-core-2.66-early -2009-nehalem-specs.html

If that is the case, it can boot and Install from the last 10.6 DVD sold in the Apple Online Store (US$20).

http://store.apple.com/us/product/MC573Z/A/mac-os-x-106-snow-leopard

When Updated to 10.6.8, you can access the Mac App Store and move to later versions, including Mavericks. You do not need to load any intermediate versions along the way. This presumes you have enough memory to run Mavericks, minimum 4GB.

You need to Back up all the files you have created. Which certainly appears to be none. The Mac Installers always intend to disturb or erase NOTHING except the prevoius versions of Mac OS X they are replacing. In most cases even a Failed Upgrade leaves all previous files intact.

Installing on the Mac Pro changes absolutely NOTHING on your iMac, even if you are using it for a Mac Pro display.

If you are using Target Disk Mode, The iMac needs to be a certain age and the Discs you use need to be "Full Retail" discs to get a Bootable image on the Mac Pro. Installing an Imac-specific image onto the Mac Pro from the "shipped in the iMac box" DVD will not work.