El capitan airport utility pro#

Everything worked fine for a few weeks and I was able to access my AE and the internet with all of my apple devices, including my IMac, my Macbook Pro and my Iphone and Ipad. Jayenare, Did you ever get your Airport Extreme reset running El Capitan ? Like you, I have an Airport Extreme (or 'AE') and a few weeks ago I updated my IMac with El Capitan. Right now I am using my mobile phone's hots I am not the most tech savvy- yet have been able to resolve all of my mac issues since i purchased in 2008 despite being told to get a new one, with clear instructions. I am including a screenshot of the error message and can provide more information.

Right now I am low on cash so even purchasing a new a harddrive just to uninstall el capitan and go back to yosemite (which is what i have read is a solution) doesn't make the most sense for me. I don't think its fair that I need to buy a new system when this one is working fine, can anyone offer any suggestions? I know everyone's response is to get updated equipment, yet everything has been working fine and all of my other devices are connecting to this Airport Extreme base, yet without a utility to set up the internet- I can't actually get it to work as a wifi router. Yes- I have a very old Airport Extreme (Model# A1034 / year 2003?) and my MacBook Pro is 2008 (Early 2008, 15in). I have the original CD's- yet they do not work as they are designed for Graphite/Snow and i get a message saying due to having a newer OS, I cannot reinstall the setup program. It also has a 'no' symbol on the application. When i try to run utilities- I get an error message 'this version of utilities does not support this base station'.

Today, I cannot setup my Airport Extreme on my computer. Last night (10/10/15) everything was working fine.

El capitan airport utility