sons inspiron 1545 wont start

[squeeky]

someone please help a usless brit?
my son has a dell inspiron 1545 but i cant get it to load .when u turn it on all we get is the dell splash screen,then a black microsoft corp screen with the green loading bar going on forever.iv tried f8 but its not acepting the admin password  cant load the disks to reeboot....please help b4 i need a new pc and window that i will throw this one out of     thanks

[Allan]

What is new or different since the last time everything worked properly (ie, new hw, new sw, virus, error, etc)?