Laptop Problems

Several problems have been occurring with my laptop recently. I have an HP Pavilion dv2000 with the 6-cell battery, if that matters.
1. I hibernated my computer when it have roughly 70% battery left, and when I turned it back on it only had 5%.
2. I set up the alarm so that it would beep and give me a pop-up balloon when it reached 9%, so that I would have time to get my power cord and plug it in. But lately it has not been giving me either the beep or the balloon and simply goes into hibernate mode when the battery level gets too low. I checked the settings and the alarm is still set up properly so I don’t know what could be wrong.
3. Sometimes a the icon of the batter with a red X appears in the taskbar when the battery level reaches around 7% or so, but sometimes it doesn’t. Combined with the lack of an audio or text alarm, I often don’t notice when my battery level is getting low and then the computer hibernates without warning.
Does anybody know what could be wrong?