my acer 5920 comes on but wont start, sceen keeps saying please waitbut wont start

[cburn1]

Laptop comes on, says starting windows then screen goes to please wait then black screen then back to please wait and does that for hours, was working one day then not the next.....tried repair reboot but asks for administrator password which i dont have, any ideas having to use tablet at mo

 

[saywhut]

Can you get into Safe mode (F8 when booting up if it's Windows 7)?

Did you forget the password, or is the PC admin no longer available?

 

[cburn1]

Can get into f8, then asks for user and admin password...don't ever remember having an administrator password, so can't go any further