Unlocking the BIOS on any PC, no matter what company actually made it, is an almost identical process. The BIOS on a PC (including your Sony Vaio) can only be accessed from one specific screen during a very small window of time. However, the one important difference is that the keyboard key that you have to strike to unlock the BIOS during this window is unique to Sony Vaio desktop and laptop computers.
Press "Power" to turn on your Sony Vaio.
Watch your monitor to see the Sony Vaio logo appear. This logo usually appears after two or three seconds.
Press "F3" to unlock the BIOS on your Sony Vaio.