IMac 24 inch El Capitan

[Desh]

Hello
I have a blank white screen on the iMac. I acquired it from a friend, fully functional. I Formatted it so I had a fresh start.
I tried to reinstall El Capitan but got a error message ~ software version corrupted. Bought a flash drive with OS to hopefully do a reinstall.
Same white screen.
Any help gratefully received.
Thanks.

 

[Rodananne]

The Flash Drive may have a macOS installer on it but not be bootable.
To test this turn the Mac off, plug in the Flash drive, Startup while holding down the Option Key. You should see any bootable source displayed. If the Flash Drive is bootable it will appear as an option. If it appears click on it and you should (eventually) see a screen with options, one should be Instal macOS.

You should also see Disk Utility. If so I would suggest you use this app first to erase the internal drive at the "media" level. That means the manufacturer's name of the HD, top of the list in the side bar when show all Disks is selected. Click on erase then you will need to name it = Macintosh HD, format it = MacOS Extended (Journalled) and map it as GUID.

If not you will need to buy a "Bootable macOS installer for El Capitan" on a USB Flash Drive which are readily available on eg. Amazon. Then follow the above directions.

Erasing it will ensure there are no conflicting leftovers from the previous user.

 

[Desh]

Hello Rodanne,
Thankyou for your reply.
When I press the on/off button on the machine, I hear a whirring like something attempting to start but not quite making it. Then I get the chime, then a blank white screen.

 

[Rodananne]

This is while holding the option key down?
At least you get the chime, that's a good sign. The whirring may be your HDD spinning up, that's normal for mechanical hard drives.