In addition to changing the local under Control Panel|Regional and Language...
I also had to change the Registry settings:
(use regedit from the commandline)
In my case I needed it to change to MM/dd/yyyy
Yours may be different.
THEN finally things like "now()" in classic ASP appear in the format I wished.
This also solves the problem of SQL Date out of range error...and yes I know there are proper ways to put dates into databases which don't lead to these problems...but when you inherit code...and they want you to keep the lights on...well you get the picture.
The regedit change worked for me with IIS on XP.