"In the state of X [no state specific advice] how long is a will valid. Example, husband dies leaves a will saying everything to wife,simple estate(home). Did not go through probate , 25 years later wife dies. Does the wife own the home 100% ? per the old will. Deed never changed in 25 years."
You should also call the title company that has the title insurance on the property. A title search or run down might verify that the house was owned by husband and wife as joint tenants so that the will might be irrelevant and the house may have automatically transferred to the wife on the husband's death. In such case just have a lawyer prepare the appropriate deed. Ask the title company what you have to do to be able to give "good title" to a buyer. Those steps will be instructive.
You should review your state's intestacy laws (who gets the property if the husband had died without the will). If the will you have bequeths the house to the wife, and state law would have done the same, then the two approaches (with the will or without) have the same result. This is certainly an easier "sale".
Did husband file an estate or inheritance tax return with state or federal authorities? If so, it may have reported the correct ownership and disposition of the property even if the deed wasn't corrected.
A real estate and estate lawyer in your area are the best bet.