What happens if both parents have died and there is no will and no property deeds?

If there is no will then in most places the holdings will have to go through probate court, and unfortunately that can be a lengthy process. During the time that probate court is making its determination, any number of things can go wrong with investments, and potential heirs will be powerless to change the assets. There is not much that you can do about that now, and there is a chance that the probate court in your area will be able to move reasonably quickly.

Deeds are usually recorded by the state, and as far as I am aware the recorded deeds would take precedence in the case of disputed ownership anyway, so not being able to find your parents' copies of deeds is probably not going to be a major isdsue. Check around with the county offices that oversee the properties.