iMac 7.1 Big problem install new OS

[Wojox]

Hello.
I got a broken iMac 7.1 as a gift
I repaired, replaced the power supply, added a 1 TB 2.5 '' drive and a T9300 processor.
I have a big problem installing Mac OS 10.6
All patches from dosdude1 work on OS 10.6 or higher.
I can't install 10.6 because iMac 7.1 always informs that the system will not start on this device?
What should I do?
I burned a few CDs, created a flash drive and nothing moves.
Nothing but 10.5.8 ?????
this iMac have last version Firmware.

 

[Fishrrman]

According to everymac.com, a 2007 iMac should be capable of running up to OS 10.11.x (El Capitan).

The factory-installed OS was 10.4.10.

Do you have access to ANOTHER Mac?
That's important, because if you have another Mac, you ought to be able to create a bootable USB flashdrive with an installer on it.

I would suggest either OS 10.6.x (Snow Leopard)
or
OS 10.8.x (Mountain Lion).

Use one of these free apps to create the USB installer:
- DiskMaker X
- Install Disk Creator
(you must use THE RIGHT VERSION of these apps for it to work).

If you DO NOT have access to another Mac, I can think of a couple of approaches:
- Try to find the UNIVERSAL 10.6.3 install DVD and install from that.
- On ebay (and perhaps other places), there are sellers who will sell you a USB flashdrive with the OS installer pre-installed and ready to boot up. Generally these sell for around $20 or so.

 

[Wojox]

I can't access a newer Mac. Maybe I'll buy it in the collection. Now I have a PowerBook G4 with OS 10.4 Tiger. I also have a PowerMac G5 PCIex and I have OS 10.8.5 here too I am just looking on eBay Snow Leopard, 10.6.3 I'm stubborn and I'll get my job. This page is helpful: https://lowendmac.com/2011/os-x-10-7-lion/ But the date shift trick doesn't work.
Thank Very much so help me...