Janette, As Jay stated, this is a very tough problem.
I would contact your local Parks and Wildlife Department and get some advice from them. They will loan you squirrel traps to catch the critters and remove them to another friendlier location.
They are pretty easy to catch, but?????
Now, babies, you just never know until its way too late. During mating season, the female squirrel will drill, saw, kick, eat, and bite and do anything to find a secure nesting place for her little ones. She will even get at an eave or alcove and start scratching and digging until she gets in. If she has the determination and drive, she will get in regardless what you do.
Now, here are a few things that you can try. Some have worked well, some have not. But, you need help.
First, go to a local sporting goods store and but some blow up owl decoys and put them strategically all around your home. Cut off all branches that over hang or touch your home. The guys can jump quite a distance, but sometimes this will help.
If you can see an entrance or exit, go to the sporting goods store again and buy some fresh Red Fox Urine. It comes in a spray bottle for archers. Spray this at the holes where the guys go in. This will work, but it disapates quite rapidly.
Get some binoculars and survey all over your home and look for the smallest of holes where the guys get in and attempt to cover up each one. Do not use wood again, use metal flashing or strong metal fabric.
you do have a problem and I do wish you good luck,