If you are trying to configure/clean/fix your PC and you want it to start in safemode, you probably press F8 and then select the safemode option. That is a perfectly fine method but can be a little time consuming if you want to start it in safemode the next few times.
Here’s an easy way to do it. Click on the Start button and in the text box labelled Run (Search for Vista), type msconfig and press enter. This will take you to a configuration panel for the operating system. Now choose the boot tab, and under boot options, check the box for safe boot.
You can leave the optional settings on Minimal, or choose a more specific setting for booting in the safemode. Now click on apply and you are all done. Windows will now boot in the safe mode by default.