Samsung G2 Portable hard drive can't be detected by my macbook

I've always used this in my macbook pro and it always work and I just used it last night. but now, it doesn't appear in my desktop nor on the sidebar. the LED light is on and I can hear the typical sound of a hard drive starting and there's slight vibration which always does before. It doesn't appear even on other mac laptops. I dont have any PC Computer near me so if you could help me with a mac solution. Thank you!