if you cant remember your windows log in password and you aint got a reset disk then your pretty much up shit street

a searcgh of the internet will reveal variuos methods of hacking and resetting the password but most of these are long winded and complicated
a simpler solution is to make use of a program called Ophcrack
Ophcrack

download the file ophcrack-live cd.iso and burn it to disk.Boot your pc with this disc in the drive and the whole process is automatic.It,ll anyalyse your system and advise what the passwords are for your user accounts.

Of course if you ever come across an unwanted laptop/pc(say no more)that is locked bobs your uncle