Hi there and welcome Susie
As the first step, can you close all programs.
Then open Finder and click on Go to folder
Then go to the folder preferences.
Locate Quark, drag it to the trash and then open Quark
Tell me if it now operates correctly please.
Unfortunately only version 184.108.40.206 will work with El Capitan you can try updating here but I have found it is difficult once you have already upgraded you need to do it before you upgrade: http://www.quark.com/support/downloads/Details.aspx?fid=277
Let me know
You may need to start with an earlier update like 9.3.1 see here: http://www.quark.com/support/downloads/Search_Results.aspx?pid=1&oid=2&ftid=2
Removing the Quark Preferences should not affect any of those other apps. Let's check some things: Reboot into the Recovery HD by choosing the ‘Apple‘ menu > Restart, then hold down the ‘Command’ + R’ keys on the keyboard during the start up process. When you see the Apple Logo you can let go. When the machine boots you may have to choose your language then you will see the OS X Utilities screen. Select the Disk Utility and then sDisk Utilityelect Continue. Then in Disk Utility select Macintosh HD in the left column (if there are two with that name or it is named something else choose the first indented item) and then on the right select the First Aid tab then select Run.
OK this is normal maintenance, let me know
Crashed? what does that even mean I'm sure your "tech" guy did exactly what I suggested you can ask customer service for a refund