How can i stop the brakes on my old cruiser from sticking?

I don't know anything about bikes, but I've got and old scwinn cruiser with bad brakes. The problem is that when they squeeze shut the side that the brake cable doesn't goto stays against the wheel rim. It's that same for front and back and I can't figure out how to get them to pull back after i stop squeezing the brake.How can i stop the brakes on my old cruiser from sticking?There are a number of things that could be wrong here. Let me start by saying that when dealing with brakes, I always suggest going to a bike shop if you don't know how to fix it. But in any case....the cable could be not freely traveling within the housing. It could be rusted or just need to lube. Try injecting some lubricant in the housing from both sides. See if that frees it up. Next, try shooting some lube into the pivot points of the brake. This could get seized up too. Finally, the spring that holds the brake caliper apart could be disengaged. Look for a spring sticking out. Hope that helps....good luck!