Mac mini reinstall

Those were necessary in order to upgrade and should have been kept with the Mac mini for troubleshooting and reinstalling.

At this point, you'll have to look for one of those (preferably a Lion USB Flash Drive) to troubleshoot the Mac mini's HDD and hope that it has not failed.

Have you tried internet recovery ?

if you try with a usb boot disk done too long ago, you will have trouble doing so.

when i did that with a 2010, i first had to recreate boot disk and trick the mac with a date nearby rather than today’s date. But even then, i was unsuccesful. Others claim to have been able to proceed this way.

But first try internet recovery.

Have you had this Mid 2007 Mac mini since it was new or did you just acquire it used..?

Do you have the original Tiger Install Disc set, a Leopard upgrade DVD, a Snow Leopard upgrade DVD or a Lion upgrade USB Flash Drive..?

If you do not have an upgrade DVD or Flash Drive, then you will need to get one of those from E-Bay.

https://www.ebay.com/itm/286178774131?

https://www.ebay.com/itm/296776743236?

FWIW while those early Mac mini's were good machines in their hay-day, that one is well beyond obsolete at 17 years old. Plus it most likely has a failed HDD, a dead Pram battery and/or some other type of hardware problems.

First check the HDD..

To do that, open Disk Utility and Run First Aid on the Macintosh HD.

Then if the HDD is OK, navigate back to Reinstall and try reinstalling Lion.

https://www.instructables.com/How-to-do-a-clean-install-of-OS-X-Lion-from-Lion/

I read this thread and have one question: What is your intended use for this Mac mini once you get it restored?

I only ask because that Mac is well obsolete and there is little to no use for it on the modern internet. Its usefulness even for email is limited. I hope your plan is simply hobby. I'd hate to see someone spend time and other resources hoping to put this old Mac to productive use. Of course, it is your time and resources to do with as you please.

Luck, my friend. 🍀