Laptop Won't Hibernate

I have a HP Pavilion laptop. When I used to close the top of it the computer would go into hibernation. Now all of a sudden when I shut the top the computer turns off and I have to reboot the system every time I want to get on. What would cause this when I didn't change any settings?

 

You have some nasties running about.....

perforum this scenario:

1 - Download and run CrapCleaner from
http://www.ccleaner.com/

2 - Run updated versions of Spybot S&D and AdAware SE (one at a time), cleaning all that may be listed.
Spybot -
http://www.safer-networking.org/en/mirrors/index.html
AdAware -
http://www.download.com/3000-2144-10045910.html
(remember to update databases before scanning)

3 - Perform an online virus scan from
http://www.ewido.net/en/onlinescan/ or
http://www.bitdefender.com/scan8/ie.html (or both if you want to).