In sounds of our hearing, i’t so simple way. How to replace a newline (well known as ENTER) become to space in Ms.Word? Just backspace and do space after that, right? But, are you sure for done by that way?  if you found just not one “enter” to be replaced, you just use  this way :

replace ^p with ” ” (blank space) or the others characters.

Further references you can find here http://support.microsoft.com/kb/95474.

All right, that’s all. ^_^