Starting ignition

I have own five Aerostars. The problem is with a 1994. I purchased it recently and have had work done on it Everything seemed to be working OK. Then the other day, I stopped at a store came out and there was no ignition! Turn the key nothing. Tried unsuccessfully five or six times nothing. Then it started, hmmm!

A few days later it happen again, then again. It has now happen five times. Where is my problem? Ignition switch, key, steering column, starter motor etc.?

Thanks
websterjim

websterjim,
need more input :)
things like does the dash display come up?
does it go through the self test when key is turned on?
or is there no power at all?

specifics help alot ;)

Laterz,