When you go to safe mode, the account is actually different than the one you normally use in most cases. It's known as the Administrator account.
Depending if it was poorly setup or not, you may be able to get into safe mode by simply hitting enter for the password.
You may also try continuously tapping f8 at system power on to get the choice of boot options. Try choosing the one that says last known good configuration or last settings that worked (or similar, I actually forget right now how it's actually worded off the top of my head.)