Windows 7 missing Administrator user login

try this...

start pc
hold F8

select safe mode with command promt

when the box appears type

net user administrator /active:yes

a mesage should come up saying successfull

reboot the pc

an account administrator should appear.... IF THIS IS YOUR ACCOUNT THEN GOOD! IF NOT PROCEED

login, go to start

control panel

system and secuity

computer management

users folder

click users

CHECK IF YOUR USERNAME IS STILL THERE... IF SO PROCEED

right click your account and click properties,

ensure the account is not disabled or locked

if the boxes are ticked untick them and save

to remove the main account

repeat the same process at the start however type

net user administrator /active:no