to remove the password download
hirens boot cd
http://www.hiren.info/pages/bootcd
then burn the image to a disc and boot the pc with it (you might have to change the boot order in the bios)
then run windows offline nt & registry editor, but this can be complicated.
the easiest way, is to download ophcrack
http://ophcrack.sourceforge.net/download.php and do as above, burn to cd and boot with it.
ophcrack is virtually automatic. let it load up and select the user gui (the top option).
then let it run for about 10-15 mins.
it will now reveal all the passwords on the pc.
write these down.
make sure to exit the program properly before shutting down pc.
now take out cd and boot into windows OS.
now type in the password
ps. i use imgburn to burn the iso image to disc, but if you have nero, this can also be used, also windows 7 has a image burner built in