Ransomware keeps coming back - HELP

I have been attacked and infected by the "your computer has been locked by the FBI" twice now. last week i was hit by it, then just today it wiped me out during final testings for my online course work.
I need this thing GONE quick and for good. How do i remove it for good?
Is this thing snatching all my passwords and info?
I need some help and info on this ransomware virus