There is no need to format the drive .. normally hibernation consumes around 2GB space on your primary activated partition (depending upon the version of operating system being used) some times even more than 3 GB's if multiple heavy applications are running in the background .... it can be disabled from the computer managment options ... or just simply right click your My computer icon ... go to properties .... then look around on the tabs .. there would be an option on one of the tabs ... can't remember the exact name of that tab ... just disable that .... and restart ... thats it ...