You can access the menu by turning on your computer and pressing the F8 key before Windows starts.
Some options, such as safe mode, start Windows in a limited state, where only the bare essentials are started.
If a problem does not reappear when you start in safe mode, you can eliminate the default settings and basic device drivers as possible causes.
Shows a list of system recovery tools you can use to repair startup problems, run diagnostics, or restore your system. This option is available only if the tools are installed on your computer's hard disk. If you have a Windows installation disc, the system recovery tools are located on the installation disc.
Starts Windows with a minimal set of drivers and services.
Starts Windows in safe mode and includes the network drivers and services needed to access the Internet or other computers on your network.
Starts Windows in safe mode with a command prompt window instead of the usual Windows interface. This option is intended for IT professionals and administrators.
Creates a file, ntbtlog.txt, that lists all the drivers that are installed during startup and that might be useful for advanced troubleshooting.
Starts Windows using your current video driver and using low resolution and refresh rate settings. You can use this mode to reset your display settings.
Starts Windows with the last registry and driver configuration that worked successfully.
Starts Windows domain controller running Active Directory so that the directory service can be restored.
Starts Windows in an advanced troubleshooting mode intended for IT professionals and system administrators.
Prevents Windows from automatically restarting if an error causes Windows to fail. Choose this option only if Windows is stuck in a loop where Windows fails, attempts to restart, and fails again repeatedly.
Allows drivers containing improper signatures to be installed.
Starts Windows in its normal mode.
More at - http://windows.microsoft.com