Despite Northwood taking an early lead, Slough were able to take a lead into the break with Stuart Swift providing the influence.
His first half strike from a free kick set Slough on their way before he assisted Sean Sonner for his first and Slough's second of the night.
Slough then consolidated their lead and ensured victory in the second half with strikes from Danny Burnell and Simon Martin along with a second for Sonner.
Northwood Line up
Parkin (Machel), Hall, Tackley, Bent, Gill, Burgess, Jackson, Windsor (Walker), Orphanou (Wallace), Jones, Lovell. Subs not used: Sharples, Williams.