GouRou was pretty much right...
What I was trying to do was (I think) the same as you,
basically, getting Apache to start with the documentroot set to a network drive's directory. Since i develop the site on a network machine, and not on my local hard drive.
First off, obviously you need permission to access that network drive - how ever you do it, be it, by logging on to windows using network authentication, etc.
BTW, I'm running Apache 2.0.44 on WinXP SP1
Basically, go to Control Panel -> Administrative Tools -> Services -> Apache
Open it up, and select the Log On tab. Under that, instead of the normal 'Local System Account', select 'This account'
and from here, enter your username (ON THE NETWORK), and pasword.
e.g. Network-Name\username
(click browse to make sure you got it right)
Click ok.
Now apache has permission to access the network using your login details.
Open the httpd.conf and set the following under the appropriate places: -
DocumentRoot "//networkComputer/Directory/To/Website"
<Directory "//networkComputer/Directory/To/Website">
And that's it!
NOW, restart / start your Apache server (I use the apache service monitor).
If it has successfully started, you're done.
Now go to a web browser (like mozilla) and enter the name of your computer where apache is running
e.g.
If it was unsuccessful, you need to first make sure you actually have rights to that network space.
So go to Explorer and Map whatever Drive to //networkComputer/Directory/To/Website
And click 'connect using a different username' to check how you are gaining access to the network (if you don't already know).
If you can map the drive, you can get apache to work using the network drive as the root of where your website files are.
Let me know how you get on.