In order to download the latest drivers, go to http://support.acer.com/drivers_download.aspx
and select the relevant model (Notebook -> Aspire -> 3810T, for example).
Then choose your current operating system (e.g. Windows 7 32-bit) and in the Application section below, you will find two power-related downloads: one is Acer's ePower Manager and the other is the DVD power utility. You download them, unpack (unzip) into a new folder and then install them one by one. If prompted to restart, do so.
They both work excellent and save you lots of power. You can check if they already work on your computer by pressing Ctrl + Shift + Esc (Windows Task Manager) and look for ePowerEvent.exe and ePowerTray.exe. You can also take a look at the Services within Windows Task Manager.