Q: Mac Mini Hard Drive

Depending if your HDD is installed in the upper or lower bay, determines how many parts you have to remove to get to it.

iFixit.com has visual instructions of how to replace a hard drive in a Mac Mini. I have done this several times and it's not that difficult. You just need to go slow and keep track of all the parts.

The OWC (Macsales.com) HDDs are very good. I recently purchased a 1TB 7200rpm HGST drive for around $65.

As far as trying to get any files off of it, you could try putting the Mini in Target Mode by restarting it while holding down the T key.. I use a Thunderbolt cable for this. I don't know what you would use with a 2007 Mac. If you're able to get the Mini in Target Mode then from the 2007 Mac you could see if you can copy files over. Hopefully, you have some sort of back up of the Mini prior to the drive failure.

Do identify your Mini:

How to identify Mac mini models - Apple Support

Yu can enter the serial number here. The SN is listed either on the bottom or back of the Min along with a model identifier.

http://www.everymac.com/ultimate-mac-lookup/

The 2011 Mac Mini 5,2 uses a discrete GPU chip and failures have been reported that give strange graphics on screen and then nothing.

One you know your model then go here and find the HD replacement video for you model Mac

https://eshop.macsales.com/installvideos/

You can connect your two Macs via FireWire and then boot the Mini in Target Disk Mode

How to use and troubleshoot FireWire target disk mode - Apple Support

and the other normally and see if yo can see the Mini's HD in Finder on the other Mac

You can also take out the HD from the Mini and place it in an enclosure or dock and connect to the other Mac

What MacBook Pro do you have? For El Capitan (and for greater than Lion) you need:

• MacBook Pro (Mid/Late 2007 or newer)

Also, with only 2 GB of RAM the MBP will be slow

The only 2.33 GHz MBP I could find here

https://en.wikipedia.org/wiki/MacBook_Pro

is a late 2006 and those can only go to Lion

I'd love to tell you exactly how old my Mini is, but I can't get to that info. My best guess is 2012.

Use your serial number:

https://support.apple.com/en-us/HT201173

Then type it into: http://www.appleserialnumberinfo.com/Desktop/index.php

You could try putting your MacMini into Target Disk mode connecting via a Firewire cable to your MBP, but if the HD is dead, you won't be able to see it.

This is why you should have been maintaining a backup.

What type of backup, TimeMachine or clone? If it is clone, you can boot from it while waiting for your HD replacement, and then use it to clone the replacement drive.

Then you'll need to wait for the HD replacement, install El Capitan on it by using Internet Recovery, then use Setup Assistant to migrate your data from the TimeMachine backup.

This points to the biggest advantage of maintaining a clone backup in addition to, or instead of, a TimeMachine backup.