Upgrading from IMac OS X v.10.3.9

If you're going that route, this info from TexasMacMan may be of use;

Mac OS X 10.5 Leopard installation system requirements

http://support.apple.com/kb/TA24950

Leopard is no longer available at the Apple Store but may be available by calling Apple Phone Sales @ 1-800-MY-APPLE (1-800-692-7753).

If you can't obtain a retail install DVD from Apple, look on eBay or Google the installer part numbers to possibly find at an on-line store. Here's what to look for:

MB427Z/A Leopard 10.5.1 install DVD

MB576Z/A Leopard 10.5.4 install DVD

MB021Z/A Leopard 10.5.6 install DVD (single user)

MB022Z/A Leopard 10.5.6 install DVD (5-user family pack)

Installing Mac OS X 10.5 Leopard

http://support.apple.com/kb/HT1544

Mac OS X 10.5 Leopard Installation and Setup Guide

http://manuals.info.apple.com/en/leopard_install-setup.pdf

After you install the base 10.5, download & install the 10.5.8 combo update at http://support.apple.com/downloads/Mac_OS_X_10_5_8_Combo_Update

If you install 10.5, you will lose Classic. If you install 10.4 or later, you'll lose the Find File to be replaced by Spotlight's Find File which can be slower. Only upgrade to either if there is need, and you are able to update your software to follow. Start with this tip, which also directs you to a tip that explains the advantages and disadvantages of Leopard as well: https://discussions.apple.com/docs/DOC-2541

You can't run Lion, or even 10.6, on PPC Macs. The best you can do is 10.5.8, but I don't recommend it for most 10.4 PPC installations.

Unfortunately, if you want Lion, you will have to bite the bullet and look for a newer Mac.

Matt

Intel Macs won't run 10.3. Go to the Apple menu, click About This Mac, and More Info. What is the model name and model identifier? (eg, "PowerMac4,1")

7 years is actually a pretty decent age for a computer! The PPC/Intel switch-over actually happened around 2006.

Matt

It is pretty tough. To upgrade to either Tiger (10.4) or Leopard (10.5) you'll need a retail installer DVD.

Leopard may be available from Apple Phone Sales, but at around $130. On Amazon or elsewhwere it's likely to $150 and up.

Tiger is even harder to find and consequently prices are even higher.

Leopard won't run Classic mode, either, so no OS9 apps will work with it.

Ultimately it depends how much you want the new(er) bells and whistles. To get further than Leopard you're going to need an Intel based Mac (Jan 2006 and later), and for Lion a Core2Duo at minimum, which means Sept/Oct 2006 or later.

A used one might still work out cheaper than trying to upgrade yours, but make sure it has at least 1GB of RAM (2GB if you plan to go to Lion).