I have a 2007 iMac and just spent $260 adding additional ram and having a service as it was going extremely slow.
I was told the hard-drive might go at any time and within 6 hrs of using it that’s just what it did. My husband wants me to fix it but I’m reluctant to do any more work on it as. I know that apple no longer sell the parts for my model so I’d only be able to get them from ebay. Opinions anyone?
The hard drives are replaceable and don’t be concerned about brand. Hard drives (HDD) in Apple computers are just branded for Apple. The only thing you need to do is format the drive for Apple usage rather than for PC usage. Just make sure you get the right interface to connect the drive ie SATA or IDE, though I would assume your one would be a SATA connector not the older IDE and the right size ie 2.5" or 3.5". HDD can be bought from most computer stores and should be a lot cheaper than buying an Apple branded drive.
Here is a video and instructions that might help you:
Regards
@grahroll
Thanks for the advice and how cool was that video - a girl, just like me!
Well I will be going ahead with fixing it 
Once again thanks for your help. Meg
My pleasure and I hope you have an easy experience of it. Though do make sure it is just the HDD that has failed and not some other component in your iMac. Also you could just buy the drive take it and your iMac to your local computer store and get them to fit it for you saving you a bit of effort, some even have fixed fee structures so you might only be up for about $140 all up.
Hi again,
I wanted to let you know that when I saw the tech guy a few days ago I explained to him that the computer had a white screen and intermittent beeping noises his response was “thats unusual” not knowing the fixit of macs to well I thought that the drive was gone, however your linking and prompting got me to look a bit further. I had previously sent the computer in to get more ram, I brought it home and it seemed to die after 3 hrs and a few downloads of programs. So it was surprising when I learnt that the white screen and 3 beeps at regular intervals meant that the ram was the problem. I found a link to show me how to access the ram and low and behold when I removed one of two of the chips the beeping went away. I eliminated the ram slot by putting the good chip in there to test it so overall it’s not a hard-drive failure it’s a dud ram chip the tech guy put in.
Overall I have spent $280 for an upgrade of 4GB, I actually thought I had 2GB of ram to begin with but it saids on the invoice 1GB and I’m still a bit sceptical about that too.
Well I must say your advice led me down a few different paths yesterday and it shows the Choice forums to be beneficial.
thanks again for your help and insight which has saved me $1000’s of dollars
Meg
If you get the RAM stick’s part number you can easily search online for it’s size, speed and suitability. The information should be on a sticker on the stick. Also if it has failed most RAM have what they call limited lifetime warranty (lifetime warranty for the first owner) these days so you are entitled to get it replaced. If the Store won’t do it contact the manufacturer or their rep here and ask for a RMA on it. You will normally need to provide a copy of the invoice/receipt with the return but don’t send the original.
And I forgot to Thank you for the feedback. I am glad I could help you. 
Didn’t have time to reply earlier, and I see you have the issue under control and know your way around the innards of your iMac, so I will just suggest that next time you know what you need, have a look at www.staticice.com.au for cheaper pricing on almost all computer, etc gear.
As with other on-line shopping, check the sites for credit card surcharges and delivery fees. Compare that the total cost (goods + cc surcharge + delivery) to the price you can buy from a store. Generally, I find even with delivery it is cheaper than buying from stores.
Some times I buy on-line via www.staticice.com.au (cheaper than in-store pricing) and go and pick up the item saving delivery cost.
My daughter bought a Macbook Air (against my advice). She recently spilt a glass of water on it, and phoned the Apple shop who said that it was unlikely it could be repaired, but they’d sell her a new one for a couple of thousand dollars. They couldn’t even look at it for a week. On the advice of a friend, she took it to the Chinese guy down the street (that should be a trade mark) and 24 hours and $400 later she had it back working like new.
The moral of this story is don’t take Apple’s word for anything. Take it to the Chinese Guy Down the Street ™.
If Apple repaired it, they’d have to give a warranty on that repair. There’s no way they’d do that once the product is water damaged. I think Apple’s advice is sound. Glad it was fixed but take care and back it up. 
The CGDtS gave it a 12 month warranty.
And yes - she’s asked for an external drive for xmas. 
I’d recommend a Time Machine if it’s purely for backups. It will back up every hour and has all the nice features for recovering. I can’t recall how many times it has saved me.
Being a apple user for over 20 years I cannot understand why you want to fix such a old computer.
The problem I see other than very slow response time from such early model is that the inability to install the latest upgrades of operating system and applications will likely cause reduced security on the net and for webpages and interface to be degraded or not even available.
You don’t always have to buy new to get later technology and updates.
For the money spent on a 2007 ‘dinosaur’ IMO you could have purchased secondhand machine of a much later generation and hence faster and likely more compatible.
