Volvo: Driving Whine, front wheel bearings, remote control car

Question
I have an unusual noise while driving my Volvo that won't repeat itself for a mechanic.  I have an '88, 240 DL, 4 door.  The noise is intermittent and sounds as though the car is winding up and down with increase/decrease of speed.  Almost like a remote control car.  I did take the car for a check up and the front wheel bearings were replaced.  I used to work for a used car dealer and consider myself fairly knowledgeable about most vehicles but I do not know anything about Volvo's.

I also have a problem with the power to defrost the windshield which is not handy in the Central NY area in the winter.

Also, I purchased this vehicle used in the Spring of this year.  I had new all season radials put on the car and it doesn't seem to want to go anywhere in the snow.  Is this due to it being a rear wheel drive, the weight of the car, or possibly the drive train?  Most say that these are little tanks so it doesn't make sense that I can't get around with it.  I'll be putting the snow tires on it this weekend in hopes that it will help.  Do you recommend putting some additional weight in the trunk?

Any help you can give me to help resolve these mysteries would be greatly appreciated.

Answer
Hello Karen! The noise could be coming from the driveshaft center bearing or the rear axle. I would have them checked. When defrositing the windshield, make sure the recirc is not on. The window will defog easier. 4 snow tires will help the car greatly.

Jimmy