deleted admin account need admin account

I deleted my admin account and now using guest account but i can't make a new admin account. Whenever i type in a name is says, The specified account name is not valid, because account names cannot contain charachters: . So i tried running cmd as an administrator then typed: net user administrator /active yes and no matter how or what i do i keep getting denied and i really need to make an admin account some programsi still cant run and projects i cant do even if i right click an d run as an administrator. So can somebody please help me.

Specified account name is not valid because of invalid characters

You can't use some characters in account names.