domain option missing from log on screen

this morning i logged onto my friends laptop.

i updated it for her, and helped change back some funky appearance problems,

but during the process i might have changed a setting on accident.

she uses her laptop at work and i guess they set it up for her to use on their secure network and at home to use the comp. she logs in using her user name, password, and domain.

but now the domain option is gone and we can even use the laptop. it says incorrect us.nm. , ps.wrd. , or domain.

i click the options button and it only gives me the turn off the computer menu.

googled it and searched for solutions all day please help