Need replacement hard drive

Thank you, Jack! Petty sure its the drive.. I can boot the iMac with an external bootable drive, but the internal hard drive appears to be dead and buried.. it'll show up on desktop, then disappear lol.. But, it boots up in mere seconds with an external bootable drive.. I'm more a programming/graphics guy and not a hardware guy, so I really appreciate the help..

Thanks again, Jack.. I currently have the iMac fired up via a bootable drive and, although limited with what I can do with it cuz there's not much software on it, I did everything I could with it jus tot make sure something else wasn't goofed up.. Surfed the net, fired up notes and other simple programs, checked out the hard drives in Disk Utility etc.. everything seems to function fine.. Unfortunately the internal hard drive icon WAS on the desktop, then disappeared.. before it did I was able to pull a few small files off it onto the external.. but, I do have everything (except applications) backed up on a different external.. So, I went ahead and ordered the Lacie SSD 2tb drive in your link.. I really think that's gonna work.. thank you so much for your help.. its pretty ANNOYING that the official Mac repair store here didn't mention that as an option.. They just told me my hard drive is dead and my best bet is to buy a new computer - which they obviously also sell.. never once mentioned your external drive fix... thank yu, again.. Steve

Jack - that's the drive I ordered.. I used the link you provided just to make sure I got the right one.. I really woulda preferred the Thunderbolt version, but didn't think it'd work.. I'll et you know when I'm up and running.. thank you so much for all your help..

Yeah, that was the killer of wanting that drive lol.. but, it runs pretty well with a regular external drive right now - maybe a TAD slower - so hoping the SSD drive will get it back to normal.. Heck, I'm excited about it..

Hey Jack! Just wanted to let you know that I finally got the external drive from your recommendation set up as the start up disk for the blow up iMac and she's running really smooth.. currently loading software on it, as we speak... It took me a while to get to it because I went ahead and got another computer to set up all my audio studio stuff on.. I'm going to use that computer strictly to record audio with.. This computer - with the external drive - will be running almost everything else: full adobe suite and all the regular stuff.. Anyways, THANK YOU so much for your help with this.. I really thought that computer was a goner, but she's back in business..!

Looked it up and I believe its 160 MB/s.. so, the new drive should be quite the improvement..