Care to elaborate?

Hi

  I bought dell insprion 6400 laptop with vindows vista home basic,recently.Everything was working fine.

Later I installed windows XP professional in it.After that, I started facing a problem with battery power.

 

   Battery is getting drained even if i close the lid of the laptop.within 2 hours 100% charge is coming down to 0%.

I noticed that standby is disabled in my laptop.

 

Could anybody help me resolve this problem.