To make hibernation unavailable in Windows 7, follow these steps:
- Click Start, and then type cmd in the Start Search box.
- In the search results list, right-click Command Prompt, and then click Run as Administrator.
- When you are prompted by User Account Control, click Continue.
- At the command prompt, type powercfg.exe /hibernate off, and then press Enter.
I used these steps to free up about 15gb of space on my c drive!