Can't edit apache2.2 httpd.conf on Windows 7

Just like Jason said in his comment -- run the editor with Administrator's rights. I had the same problem. Right-clicked on my Notepad++ launcher, chose "Run as administrator", opened the file and off you go!

I know this is a necro, but I found this after a quick googling and wanted to help out any other weary netizens.

It's because the permissions are set to read only for the users group during the apache installer. To fix this. Rightclick the file, select properties. On the security tab, select users and click 'edit'. Then add write privileges to the users group.

There's a good explanation for this problem, it's because of VirutalStore

http://blog.netscraps.com/bugs/apache-httpd-conf-changes-ignored-in-windows-7.html