Are you referring to DW4 (circa 2001) or DW CS4 (circa 2008)?
Judging by your previous posts, I assume you're referring to CS4?
there is a little nasty trick:
Your file in question begins for example with a lowercase letter.
Save this file, but first change the first letter into a capital letter.
DW asks you whether you want to overwrite the old file --> Yes.
When the file is stored the previous file amazingly is deleted. (Control it by "open file).
Of course this works the other way too as well, it's enough to change only one/the first letter.
I am taking about DW CS4 that came out in the last year or so
I don't necessarily want to delete the old file. I just want to modify it and rename it to a new file
... and the old file should close!?
Yes, I want the old file to just close in the Deamweaver window. So that the only file open now is the new file.