iMac shutdown, Apple logo came on and the status bar only went about halfway.

Hmm, sorry, but there are numerous iMac models, starting in Late 2009, that had this CPU option. However, if it is currently running macOS 11.7 (Big Sur), it could be a Mid 2014 model or newer.

What I was looking for would be the Model Identifier, something like: iMac14,4.

Regardless, chances are its internal drive can be replaced, but it would be a relatively difficult task for a DIYer. As far as Apple doing the replacement, it would have to be a 2017 model or newer to still be supported.

Finally, to get an idea of the cost involved, see this link:

• Apple Repair and Repair Status Check - Official Apple Support

... something I would like to add. This may not be an issue with your Mac's drive at all. Typically, when you see the progress bar on your Mac's display, it is going through the process of loading kexts (kernel extension). These are primarily device drivers. One quick test for this is to try starting up your Mac in Safe Mode. This should prevent any third-party kexts from loading. Alternately, you can remove any peripherals attached to your Mac, except the keyboard & mouse, to see if the progress bar completes and you are presented with the macOS Desktop.

Let's start with can you provide us with the exact model number of your iMac? This will help determine if Apple still supports it, or if it is considered Vintage or Obsolete ... which have little or no support, respectively from Apple.

In the mean time, take a look at the following user tip to see if it can help narrow down what may be the issue with getting your Mac to start up successfully.

Ref: Mac Basic Startup Troubleshooting Steps - Apple Community

That is not a model year, if it’s a 2017 or older iMac it is considered vintage by Apple. An Apple Store will not work on Vintage Macs, you may find an independent Apple Authorized Service Provider that will though. If it’s vintage then it would be wise to replace it.

If your HD has died and you were not backing up using Time Machine or some other method then your data is gone. There are data recovery services available however for most they are prohibitively expensive, starting at $10K. This is why using Time Machine is absolutely critical or if you choose some other backup method that it be done at least daily.

sorry to tell you what you did not want to hear. However if you are lucky and your HD did not crash then back it up ASAP using Time Machine!!!!!!!!!!!

Well at least your photos are safe! Your genealogy research, well good luck. Hopefully the data recovery service can get the information at a cost that does not break the bank! On the new Mac mini, please ensure it is being backed up using Time Machine, if somehow you are not familiar with Time Machine then please read Back up your Mac with Time Machine. You will need an External Hard Disk to backup to (don't worry they are not expensive), PLEASE do not buy Walmart quality EHDs like WD, Seagate, Toshiba etc. These are very cheap and have a high failure rate, and believe me they fail exactly when you need them most, it's almost like they know how to stick it to you! Operating ANY computer without a daily backup plan is playing Russian Roulette, eventually it will get you. It's not a matter of "if" its a matter of when!

Get yourself a high quality drive such as a OWC Mercury Elite Pro. In fact get 2-3, it sounds like you need additional space for the MM based on your comments about an external drive being just about full. NEVER EVER attempt to use a Time Machine External Hard Disk for additional storage. Why, because when that drive eventually fails (all HD's do) you will have lost your backup and the data stored on it, this is why I am suggesting buying 2-3 EHD's .

As for creating a new Photos's library, please click Create additional photo libraries in Photos on Mac - Apple Support

You are learning some valuable and painful lessons, please just ensure you don't make the same mistakes again as your data is precious to you!