It is possible that the Hiberfile is corrupted.
You will need to show hidden files.
I am not sure this will work in 7, I haven't had to deal with this in 7 yet.
Go into your power settings and disable hibernation. Reboot.
The hiberfile should go away from the c: drive. If not,, delete it.
Go back in to the power settings and set up hibernation again. Reboot and then try it.
The way I do it is different. I boot My BartPE flash drive and just delete the Hiberfile and reboot. This is kinda technical to build. But, you could try UBCD4Win
You may try booting to Safe Mode and see if you can just delete the Hiberfile from there.