My acer laptop battery is not working it shows 98% but after using it for few mi

[myacer20]

Hello,
my acer laptop battery is not working properly it shows 98% and it show only 26 minutes but after using it for few minutes its goes down to 10% before it was not like this it used to show 2 hrs or more again i charge it goes to 100% in around 45 minutes but after that the same problem please help me

 

[buwish]

It's probably a sign that the battery is on its way out. However, have you recently updated to Windows 7 though?

 

[myacer20]

hello
no i havn't updated to window 7 my laptop window is xp