Chosen Solution

So, as I order parts to make repairs and upgrades, I can’t help but wonder how many times DIY-ers have damaged their computer while trying to fix it. Adding RAM; pretty easy. Replace Hard drive and fan; listed as “Moderate”. Replace CPU; “Difficult”. Gulp! I’m hoping to end up with a faster more useful iMac and not a novelty lamp stand! Anyone heard any horror stories or willing to confess?

Maybe ruining a device is a bit of an extreme outcome, but it’s impossible to learn without mistakes, technicians included. If you look at the first 10 pages’ titles of the forum you can count quite a number of people asking for help for something happened after replacing this or replacing that..some may be bad parts, but most are just a lack of experience. Ebay makes a fortune every day by selling things broken by DIYers and wannabe technicians ;) That said, guides on iFixit are a great gift and usually very accurate, especially on Apple products. If you follow guides with time and patience you should be well off..if something doesn’t seem to match read the guide again, search for further pictures and ask for help. Very important, be well organized before start, get all the tools you need and plenty of space for work. Keep a phone or camera aside and take pictures yourself, they’ll probably turn out useful. Enjoy your repair !

I’ve messed a few up but I’ve been doing it for 35 years. First, CPU upgrades are not near as effective as upgrading your RAM and hard drive. (much easier things to do). You learn by your mistakes, same as the rest of things in your life. In the case of computers it is usually best to learn from others mistakes. Also it is better to start with making simple repairs first and build up you confidence and experience. How about telling us your exact machine and get some advice from experts before just jumping in the water? If you don’t know, the information is on the bottom of the stand. iMacs. in general. do not make good lamp stands except for the 2004 G4 iMac.

UPDATE You have this machine: Apple iMac “Core 2 Duo” 2.4 20-Inch (Al) Specs Identifiers: Mid-2007 - MA877LL - iMac7,1 - A1224 -  2133 https://everymac.com/systems/apple/imac/… Standard RAM:1 GBMaximum RAM:6 GB* Details:1 GB of RAM is installed as a single SO-DIMM module. RAM Type:PC2-5300 DDR2Min. RAM Speed:667 MHz The highest CPU you can upgrade to that Apple produced is the: 2.8 GHz Intel X7900 Core 2 Extreme, 44W drawI would not advise trying to run High Sierra. It really needs 8 GB of RAM.El Capitan is a fine stable system.

Thanks to @mayer @danj & @arbaman for your thoughtful and instructive advice. Yes, that G4 is incredibly stylish! What I have is a 20" iMac 7,1 EMC 2133 2.4 GHz Core 2 Duo Model A1224. It has 4GB of RAM and I will be adding 2 additional GB for the first step. The hard drive is the original 320GB WD, but the fan gave out (AHT Failure Code:    4MOT/1/40000003: HDD) and since I have to go in that deep to replace the fan, I thought I would go ahead and do the other upgrades at the same time. I have ordered the Samsung 860 EVO 500GB SSD (thanks there for good advice from @danj) and will keep the 320 WD as an external drive. I realize that the RAM and hard drive will make the most difference in terms of speed, but once again, knowing how far I would have to dig into the guts of the machine, and having read Mark Sokolovsky ‘s article CPU Upgrades So 2007 iMacs Can Run High Sierra I thought I would pull out all the stops, get an Intel Core 2 Duo T9500 CPU 2.60GHz and just keep going! This is indeed an amazing and informative site! As @arbaman said, the guides on iFixit are a “great gift” and the prompt and personal response from all of you here answering questions and willing to share your knowledge and experience is incredibly supportive. Thanks again.