Yes, you can. You need to buy a straightening brush from a drug store. All you do is point the dryer straight down over your wet hair and comb through it with the brush. Ta-da!
Its really easy to straighten your hair with a hair-dryer and slightly harder with a straightener. To straighten your hair using a hair-dryer* you need to comb/brush your hair then get a hair-dryer...
Straightening hair won't necessarily cause you to lose hair, though it will damage it causing breakage. I recommend taking precautions. Go for a hot oil treatment(use coconut oil/extra virgin olive...
There are over the counter cream straighteners available, but I would strongly advise against using these. They can permanently damage your hair to the point where it looks like a weird clown wig....