Answer:

DOS

Answer	Crossword Clue
DOS	John .... Passos
DOS	MS-..
DOS	Window's predecessor

DOS	Windows precursor
DOS	.. and don'ts
DOS	... Equis
DOS	Permissible actions
DOS	Two, in Tijuana
DOS	Uno + uno
DOS	Good-etiquette items
DOS	Salon jobs

DOS	.. Equis
DOS	Old PC platform
DOS	Wingdings
DOS	Recommended actions
DOS	Antepenultimate countdown número
DOS	Hairstylist's creations
DOS	Early PC platform
DOS	Two for Juan?

DOS	A couple in Cancún?
DOS	Author John ... Passos
DOS	Two in Toledo
DOS	Bobs and flips, say
DOS	It has a command-line interface
DOS	Shindigs
DOS	Lavish parties
DOS	Partners of don'ts

DOS	They're recommended
DOS	Afros, e.g.
DOS	Hair arrangements
DOS	Desirable activities
DOS	Hairstyles
DOS	Rules to follow
DOS	Styles
DOS	They're highly recommended

DOS	Windows preceder
DOS	Balls, e.g.
DOS	Advisor's list
DOS	Coifs
DOS	Flips and buns