mmm....
What do you want someone to come up with some magic code to make your OS boot from a Floppy disc and then execute an EXE file?
If you had any idea of how to make an OS you would know how an x86 PC boots. Or at least you would understand if someone told you how it worked in sufficent detail. You might have accomplished that already and I congratulate you on that. Now on the the exe issue. exe files have had different stuctures over the years. I dont understand what you mean by exe support really. I take it you want a program compiled on windows using VC or whatever to suddenly run on your OS. If that is the case then I think you need to sit down and do some more study. It is one thing making you OS capable of executing a binary that has the same stucture as a PE32 EXE and it is another to make a PE32 file linked on windows acutally work on your OS.
Asking about creating an OS here is like walking into a playschool and asking some 5 year olds on how to drive a car. They might know that what the stearing wheel is and what it does, but if you ask them about clutch control they will look at you blankly. There are some clever people here but they lack the knowledge on these things as they have not been to university. There are maybe 5 people out of the 30 or so regular members who would be able to do what you want. Creating an OS is fine, but dont try to do it without the first idea of how to do it. I dont know what education you have but by the way you post your questions I doubt you have a CS degree. There are books on OS design and I suggest you find one and read it. Then you will be better equipped to be able to start designing an OS.
edit DaWei's post is far more to the post so forget what I have just rambled on about.
