There's a program called Tuneup utilities. If you buy/download that there's a feature which enables you to delete your hibernation file (mine was 17GB last I checked!) and delete any restore points. Deleting the later isn't usually recommended but if you're strapped for space then you can clear up between 2-8GB more from that.
I never use hibernation and find it utterly pointless.
I never use hibernation and find it utterly pointless.