Microsoft has announced that the first service pack for Windows 7 will be now automatically applied to all Windows 7 machines over the coming weeks and you should prepare your computer now From Neowin:

Not all PCs running Windows 7 RTM (RTM will no longer be supported after April 9th, 2013) will receive the update as those machines that are managed by a Microsoft management tool such as Systems Center Configuration Manager (SCCM) or WSUS Server will be able to void SP1 if necessary.

Seeing that SP1 includes many security enhancements and general bug fixes for the OS, it’s hard to find a reason why the average consumer would not want the update on their machine.

 Windows 7 SP1 automatic installation will start happening tomorrow