I know this is probably a much covered topic, but please excuse me...I am new, not too computer savvy. I have an iMac G5- 2ghz- 17". It currently has 512 ram. I know that I can upgrade to a max of 2ghz. I have been warned about inferior ram. 1. Where is a reliable source for ram (being that I know nothing!!) 2. I would love to upgrade my operating system( I run OSX version 10.4.11) .to allow for all the new stuff that is out there. What do I need to do to upgrade my OS? Is it worth it? 3. I cannot afford the new i-Mac's ($1600), so I want to bring this one as far up to the year 2010 as I can (within reason). 4. What improvements can I expect with more memory? Any ideas? If so, please be gentle with the tech talk. A.