Download this ISO file of your version Windows 7: http://msft.digitalrivercontent.net/win/X17-58997.iso
Windows 7 Home Premium x64 English
Burn the ISO of your licensed version to DVD or write to flash stick using Windows 7 USB-DVD Download Tool.
Then boot the installer to clean reinstall using the Product Key on COA sticker, following these steps to get a perfect reinstall of factory OEM: Reinstalling Windows 7
As it says in the steps for reinstall, the Windows 7 installer is driver-complete with newer arriving quickly via optional Windows Updates.
Any drivers then missing in Device Manager can be found on the Sony Support Downloads webpage for your model here: http://www.sony-asia.com/support/product/VPCEB15FG
Put the wireless driver on a stick or CD first so you can get online quickly to get these drivers updates.
Looking at the apps available I would wait to see if you need the added battery support before installing it, because this and the rest of the factory bloatware often has better versions built into Windows 7.