Ok, this could get a little complicated, and your level of engine hacking skills makes it even harder... I would recommend you to go to a professional mechanic, go back to the dealer, or at least ask someone who knows the basics of how a car engine works (you will surely have some colleague on work who can take a quick look at it)
There are four steps of the ignition key,
- 0 - Off
- 1 - Pre ignition (enables some of the electrical system)
- 2 - Ignition (enables more or less all of the e.system)
- 3 - Crank (This is the spring loaded step that makes your starter turnover the engine)
When you say ON do you mean before you hit crank or during crank?
If it's before you hit the crank it could be some kind of electrical pump or engine that is bad or has run dry or something. My first thought is the fuel pump. In that case it will probably need replacing.
If it's during crank it could either be the starter engine solenoid that doesn't insert the "gear" for the starter engine. This will probably also need replacing but you could try knocking it gently with a rubber hammer to see if that makes any difference (preferably when someone is "cranking").
It could also be a belt that is old/dry/loose, which makes the "squeaking" sound, but then the fact that it's hard to start is due to something else, and this squeaking should most likely be there also after the engine has started.
Bonus case: are you sure that it's not just the standard sound of an old car cranking/starting? (just as in the previous case this has nothing to do with the fact that the car is hard to start)