When you switch on your TV, the screen flickers to life almost instantly. Similarly, turn on a mobile phone and it’s ready to make calls within a couple of seconds. The typical Windows PC, though, can seem to take forever to get going after the power button has been pressed, but why?

The start-up process
The moment it’s switched on, a PC carries out a number of self-tests, checking that components such as the processor, memory and hard disk are present. Information about these tests may be displayed on screen or hidden behind a manufacturer’s logo.

All of this is handled by the Bios (or basic input/output system). This is built into the PC and has nothing to do with Windows – it’s just enough to get the computer into a state where it’s ready to run an operating system such as Windows.

Next, the Bios searches the hard disk for the Master Boot Record (MBR). This is the PC’s first contact with Windows and, when the MBR is found, the screen will go momentarily blank. If Windows has previously failed to load, or the F8 key is pressed, a boot menu will appear offering different ways for Windows to proceed such as Safe Mode and Last Known Good Configuration.

Next, Windows loads the files, drivers and settings it needs into the computer’s memory and it is at this point that the Windows logo appears on screen. Once complete, the Welcome screen appears and you may be prompted to log on to your user account (depending on how Windows is set up). Any user settings will be applied and the Windows Desktop will appear.

The start-up process isn’t quite finished, though: any programs set to launch with Windows are now loaded. If there are a lot of these, it could be a matter of minutes before you are able to exercise full control over the PC.

If you want to see exactly what happens when Windows loads, hold down the Windows key and press R to bring up the Run dialogue box, type msconfig and press Enter. This launches the System Configuration tool. Switch to the Boot tab (BOOT.INI in XP) and tick ‘OS boot information’ (or ‘/SOS’ in XP). Click OK followed by Restart for a glimpse behind the scenes.