Blower motor quit entirely all speeds, was working yesterday no noises, checked 25 amp fuse is OK, been reading online about resistor problems of others, any other uses or how to check??

You need to turn the key on and the blower fan switch on and check for power at blower motor wires to eliminate the motor,if no power check the resistor for power,the blower motor wires plug into the resistor

If things aren't running, about the best way to check the resistors is to find them and remove them... A visual inspection should tell you alot. Resistor wires that look like they have bubbled, scorched or cracked are a sure sign of failure. What is odd though is that typically if the resistor is the defective part, high speed will still work since it usually bypasses the resistor and goes direct to the fan motor... hmmm.
About the only issue I've run into with blower motors is that the brushes will wear down to nothing and there's no way of applying power to the motor. But the only vehicles I've ever encountered that on were really old. Unless Buick put in some real trash brushes, I can't imagine a person being able to run the blower long enough in 4-5 years to cause them to be eaten up like that.
I hope things work out for you.

THE QUICK WAY TO CHECK IS REMOVE BLOWER MOTOR HOT WIRE IT USING JUMPER WIRES TO CAR BATTERY.IF MOTOR RUN YOU HAVE FAULTY HEATER AND AC CONTROL MODULE OR CONTROL PANEL.IF BLOWER MOTOR DONT WORK REPLACE IT.