The key to the door of real estate is financing! 

Then I got lucky to marry someone like minded (and I recall the Millionaire Next Door (great book) also found that having a good "defense" or saving money was a key, common theme of the high net worth accumulators of wealth in the US)...Back to the question, I saved some money, but then I did not just bury it in the back yard (where you actually lose money due to inflation, or even put it in a savings account which also loses money relative to inflation), but I read Peter Lynch, Warren Buffett, John Bogle and put what little I saved (and we saved post marriage) into quality stocks and index funds...

There are stickers on the door that it has been winterized.

Each unit has a basic interior door connecting to the stairs and we hear everything from the tenant going up and down the steps to him cooking even his laundry machine sometimes.

In October 2014 we had a sheriff sale notice on the door, landlord screwed us.

I am new to this but I am going to buy a house at a auction the promblem is they are still living there.Somebody told me I should right a letter to the home owner than go knock on there door .How should I write this letter?

You can send out mailer post cards to neighborhoods where you would like to take on buyers and sellers.Some agents go door knocking for business.Your brokerage whomever you go with should be able to offer you some advice on how to get started. 

I would appreciate if anyone can help me with the numbers on my first property, to see if I'm off or on the right track.Purchase price         850,000Closing & holding cost    65,000Rehab estimated      400,000-450,000ARV conservative      1,500,0003 houses next door was sold for 1,700,000Estimated profit conservative 185,000Estimated profit in best case   335,000Estimated profit in worst case 135,000 It has also a negative that I don't have another exit plan accept selling.Can anyone please advise if it's something worth looking at?

The deferred maintenance arent major items but they need to be taken care of....landscaping, replace some sod, paint the exterior, minor drywall repairs, replace a shower door...overall the house is solid.

No pun intended :-)Right now I have 46 front doors and soon to be 55-60 front doors.