if u cant even get into windows then try this.
1-st easy road on the log on screen pres ALT-CTRL-DEL and on the classic logon that will apear trype Administrator on the user and blank pass
if u have the built in admin enabled and did not set passw to it when installing it will boot nicely and then u can change ur users pass in the controll panel users menu.
2-nd road simply get from someone or download from someone Hirens boot cd and when booting from hirens u will find among its tools the reset passw tool witch will let u reset any users pass in ur pc to blank .works on any pc on any user and will solve this problem 100%