2010 21.5”iMac

Hi,

My main computer is a 2010 21.5" iMac with a 500GB hard drive and 8 gigabytes of ram and it is ok for web browsing and watching movies but is horrible for everything else like if you need to use Photoshop, Houdini, Illustrator, Adobe Animate or Dreamweaver it is absolutely horrible, but if you think it is worth it buy it

That might help if it does not please let me know.

What sort of computing do you do? It's not a gaming machine and will not work well for that.

How much RAM is in the iMac? 8 GB should be the minimum amount to have for today's systems and apps, more if you can afford it particularly with an 8 year old model.

Also how big is the hard drive?

Has your friend installed the original system that came with it? You say he completed a factory reset. Did he following these instructions: What to do before you sell or give away your Mac - Apple Support.