Install OS after new SSD fitted to iMac

[joham]

I have just fitted a new SSD to my older iMac7,1 (2.4 Duo 1GB) and have a blank screen on start-up with a flashing question-mark in a file folder showing.
Have tried Control-R on start-up with the same result.
Next I inserted the Snow Leopard Install disk and got the message: "you need to restart the computer".
On restart I get a blank screen & the dvd drive seems to run continuously.
Next I inserted my Time Machine back-up HD and restarted- result: a slower flashing Question mark-file symbol.
Dead end!!
The SSD install instructions say to format the new drive but I can't find instructions for same.
I have a MacBook Air that may be useful.
Thanks for any help!!

 

[Spawn_Dooley]

Hi, what OS version is on your iMac?

Have you tried all of the startup keyboard shortcuts?

• Command (⌘)-R. Install the latest macOS that was installed on your Mac, without upgrading to a later version.*
• Option-Command-R. Upgrade to the latest macOS that is compatible with your Mac.**
• Shift-Option-Command-R Requires macOS Sierra 10.12.4 or later Install the macOS that came with your Mac, or the version closest to it that is still available.

** If you haven't already updated to macOS Sierra 10.12.4 or later, Option-Command-R installs the macOS that came with your Mac, or the version closest to it that is still available.

How to reinstall macOS

 

[joham]

Thx for your response Spawn_Dooley.
Not sure now what OS but it's an oldie- the iMac is a 2007 version. I'm told this system can only go up to El Capitan.
Have tried the shortcuts you list without success.
there is nothing on the SDD as it's brand new.
I still have the old HDD which is still operable.
It's got me stumped.

 

[Spawn_Dooley]

Do you have a Firewire cable? You might be able to connect the 2 macs & use. Target Disc Mode to mount your iMac's HD onto the MBA's desktop then you would be able to format the drive using Disk Utility on the MBA.

https://support.apple.com/en-au/HT201462

It appears that as the SSD is brand spankers, the recovery partition is missing for the meantime.

Your iMac likely originally shipped with Mac OS Lion 10.4. Once the MBA formats & partitions the SSD in the iMac then you can try booting the iMac from the Snow Leopard disk ... if you've purchased that disk from eBay or the like, it needs to be the Full Universal Install version not the grey disc that used to come with Macs.