i am posting for first time, sorry if this is not the right place...

i have windows 7 username "lolax" and no password...
i installed ubuntu 12.10 in d drive using wubi...(inside windows which can be uninstalled from control panel) when installing it asks username and password, i entered "tanmay" as username and some password... and then installation started...

after the installation there was only 1 username of ubuntu "lolax" and the password was exactly which i wanted...
i tried to add user "tanmay" but it says user already exists...

plz help.. i want to keep only one user "tanmay"...

thanks in advance