Compaq Laptop keeps prompting Replce the battery!

My daughter laptop is an HP Compaq 615 installed with Win 7 Home Premium and is about 8-months old, i.e. should be still under the 12-months manufacturer warrenty period. To day it is always prompting with "Your battery needs to be replaced" and with a CROSS adjacent to the battery ICON on the Task Bar. However despite that, it appears that the laptop's battery is still accepting charge fine, i.e. with its percentage increasing with time to 100% eventually. However my gut feeling is tht laptop working time is comparately LESS now when working just on the battery. Could it be a sign of its battery degradation and needs replcaement?? Or it is something else?

Hmm, a lot of manufacturers make a battery calibration tool. If they don't, just leave the power on 'Always on' all night on battery and windows should recalibrate.

Thank you for your reply! I'll check whether HP has provided with a utility for calibrate my laptop battery.In the mean time, could you confirm I should leave my laptop on with both Battery in and AC Adapter still charging the battery, or just to leave on with battery ONLY without the AC Adapter? With only the battery power without the AC Adapter, my laptop will not last on though!
Thank you

Just on the battery, no ac power, and on high power mode (in windows 7 it is under power>show additional plans>high performance). Need to stop the laptop hibernating at the end too, or at least turn it back on after it hibernates and make it switch itself off. There are quite a few guides to it;
http://www.windows7news.com/2010/01/31/battery-life-...
http://www.google.co.uk/search?q=battery+calibration...

The idea is that windows times how long it takes the battery to run out and it will use that time as an estimate the next time it's on batteries. Sometimes it can get into a state where, due to a previous glitch in the timing, it thinks the battery will run out immediately so it gives you a red x straight away.

If I read 12eason correctly they are suggesting switching off all power saving and leaving the laptop on battery until it dies. If it is correct then this should allow windows to recognise the available power in the battery and therefore reset its settings to stop telling you the battery is running low (if it is just windows getting it wrong).

If the battery life is significantly less than it was when you first got the laptop then trying to get it replaced under warranty may be the best course of action (batteries do degrade over time but if the difference is large then it sounds like a faulty cell).

Thanks for the hints! I will try to run with Battery power first until my laptop dies to see whether Win 7 will re-calibrate itself. If that does it and my laptop battery drain is VERY similar to before then I would say my problem is solved. However if either the Windows re-calibration isn't solved or the battery drain becoming significantly degraded, then I will raise a "warranty" return to the Supplier!
Thanks everyone.

This is just an update for my situations! Draining my laptop battery out without plugging in the AC Adapter did not solve my problems, i.e. it still prompted "Considering to replace the battery" plus my battery seemed to not holding its charges too well. I phoned up HP UK to ask for their "warranty repair" and they asked me to run their HP Support Assistance utility already installed in my laptop, within which there was an HP Battery Check SW which I had run it subsequently and reported my battery needing Replacement! So HP agreed that they would deliver me a direct replacement battery FREE under their warranty because my laptop is under 12-months old! They seemed to suggest that I should remove the battery from my laptop whenever I am using the AC Adapter only may be a good idea to conserve battery life,

In reply to a post by OCdragon:

They seemed to suggest that I should remove the battery from my laptop whenever I am using the AC Adapter only may be a good idea to conserve battery life,

That's a common recommendation if the laptop is normally used on mains power.

Although the control circuitry should prevent it being overcharged, their life is markedly shortened if they routinely run at higher temperatures.

Some people suggest they are best stored in the fridge when not in use, but I'm not sure about going that far!

Well, that's a good result. The suggestion about removing the battery is because of 'battery memory' I'd imagine. If you repeatedly discharge and recharge by only small amounts, the battery will build up a resistance to charge (or something like that), effectively reducing the capacity. I actually thought they had fixed that problem with lithium ion batteries though.

Still probably a problem to some extent. But for some laptops it may not be a good idea to remove the battery - mine especially as quite often when I move around on the sofa the power cable falls out the back - if there wasn't a battery my laptop would go off about twice an evening

Plus the battery acts as a great UPS for the machine in case of power cuts.