Sentences: Double or Single Space?

[Galaki]

Final-Fan said:

Galaki said:
Single space
>
Double space
>
>
Isn't that what you're talking about?

No. There is one space after my first sentence ("No").  There are two sentences after my second.  SENTENCE, not PARAGRAPH, like it says in the thread title and throughout the OP. 

Just bugging you :)