Adding spaces to text data in a cell

[ParisFan43]

I am an Excel Beginner and need help adding spaces to text within a database-style spreadsheet with customer names and addresses (street, city, state, zip) that I am trying to clean up to create a mailing list. This information has been compiled from an outside program and saved as an Excel spreadsheet. There are thousands of customers within this spreadsheet.

I am using Excel 2007.

Often times, the text for a customer's street address will look something like this:

1234nw121st
789mainst
9510windingridgeroadn

I need a way to separate the text to look like this when finished:

1234 NW 121 St
789 Main St
9510 Winding Ridge Rd N

Can someone explain to me (in layman's terms please!) how I would go about doing this? I tried to separate the data using "Text to Columns" but since the program thinks the text is one long word, it didn't split it apart into multiple cells for me.

Any and all help would be greatly appreciated.

Thanks!

ParisFan