Really strange battery problem

My E1505's battery started this a few days ago (it has less than 100 cycles, so it it NOT dead yet, and it still gives more than 2 hours before the notebook shuts down).

When AC unplugged:
The battery indicator on the E1505 is solid orange although the battery is full.
BIOS says the battery not exists.
When booted into XP, XP says it is running on AC power, no battery installed.
I can get more than 2 hours before the E1505 shutdown itself (all the power management disabled).

When AC plugged in:
Battery charge light on the E1505 is solid green, and will turn off in 2 hours which means the battery is charging correctly and can be fully charged.
BIOS says the battery not exists.
When booted into XP, XP says it is running on AC power, no battery installed. After unplugged the AC, still says running on AC, no battery installed.
I can get more than 2 hours before the E1505 shutdown itself (all the power management disabled)

Now the real problem is I can not figure out how much juice are left in the battery so I can config the power option to let the notebook off when it has less than 10%, since run the battery all the way down to zero will kill the battery in no time!

Anyone can help?

 

Take it out and blow on it....
Worked for NESes