Clean Install of El Capitan MacOS on 2008 Mac Desktop
How long does this install take? I started the install at 7 pm last night and it’s now 11:43 am the next day and it’s still only at 75%…..
iMac, OS X 10.11
Typical install of the OS takes less than an hour or so.
If the process is taking significantly longer, then there is something going on. Potential problems include weak wi-fi signal or problematic internet connection, possibly a hard drive that is failing or failed.
Your computer is seventeen (!) years old. It wouldn't be surprising to learn that the HD is struggling.
What is your plan for this old computer?
It may be wisest to simply drop it off at an Apple Store for recycling rather than spend time and energy trying to get it back to running condition. It's an obsolete machine that is no longer supported and cannot run a supported OS. Sustaining a productive internet connection will be more and more difficult as time passes.