I'm sorry, but did you say DOS based system?
I learned to program in DOS... two decades ago. Perhaps your company should upgrade both the system and your coworkers to something a little more recent?
Other than that, I know the feeling. I used to be tier 1 & 2 helpdesk at my previous employer - after volunteering to assist the IT manager with general hardware repairs. I should have know better.
And, of course, I'm now the 'go to' guy for IT issues. Fortunately, I don't have admin access so for a lot of the problems I get to refer them to our helpdesk.