I have a Dell Dem E310 running XP. It was working great for a long time and now it won't hibernate. The LCD will blank out but the PC won't turn off. My settings in Control Panel under Power Options is as follows: Under Power Schemes Tab: "set to home/office desk" and "hibernates after 20 min". Under Hibernate Tab: Enable box is checked. What can I do to fix it? I'm not getting any error codes or messages.