How easy is it to replace iMac (2010) hard drive

It's not that hard. You just need the right tools.

I think I just youtubed it on how to do it.

 

Take a look at iFixit guide for replacing the HDD, it can be done with the right tools:

http://www.ifixit.com/Guide/iMac+Intel+27-Inch+EMC+2309+and+2374+Hard+Drive+Replacement/1634/1

 

Did my 2010 i3 a few months back . You'll need a pair of suction cups to get the cover glass off , and some Torx drivers to get the LCD off . I found that the hard part was disconnecting the LCD cables , I've got big hands and there's not a whole lot of room between the panel and the rest of the computer . There's 4 cables to disconnect . The 2 left arrows come off pretty easy , the third arrow is the LCD temp. sensor , be careful with this , or CAREFULLY peel it off the back of the lcd . The socket that's circled is the worst , it's real fragile . To get the cable off , there's a pull tab which releases a cable lock, this lock needs to be rotated up toward the top of the computer and then the ribbon cable needs to be pulled vertically (to the top of the computer , not toward you) out of the socket , without lifting away from the logic board. Once the LCD is off , the rest of the job is straight forward . Just be REAL CAREFUL reinserting the ribbon cable , it goes in flat ,don't angle it .Remember to reclip the cable lock . Get the same brand HDD as you have in the machine. Just know that aftermarket HDD's don't have Apple's embedded fan speed software, so upon reassembly and OS installation , the HDD fan will run full speed , download a copy of SSD fan control ( its free)and run it in SMART mode , this will control the HDD fan and quiet things down . Just know that it doesn't control fan speed under Boot Camp , so if you need Windows , use Parallels , or VM Ware


Take your time , look over the iFixit directions a few times and make sure you have a well lit , quiet area to work in . Good Luck!!

 

I just replaced the 1TB HD with a 120GB SSD in my mid-2010 21.5" iMac. It's not that hard. Someoldguy's post is a good summary of what to be careful with when removing the screen; other than that it's a piece of cake. I would also have a can of compressed air to blow any lint off the screen right before you put the glass back on too.

Oh, and if you want to feel like you just bought a new computer, I strongly recommend replacing that HD with an SSD instead; go with an external HD if you need storage. It's like adding nitrous to your car.