private browsing - Why is "New Incognito Window" disabled in Chrome?

I'm trying to use an incognito window so that I can test have a clean slate on cookies without restarting my browser. Unfortunately, incognito windows are disabled for some reason. Does anyone know why that is? I'm on Windows 7 using Chrome 18.0.1025.168 m.

Answer

Simply add the following dword entry in the registry as this link describes:

Windows registry location:

Software\Policies\Google\Chrome\IncognitoModeAvailability

Supported on:

Google Chrome (Linux, Mac, Windows) since version 14  
Google Chrome OS (Google Chrome OS) since version 0.14

Description:

Specifies whether the user may open pages in Incognito mode in Google Chrome. If 'Enabled' is selected, pages may be opened in Incognito mode. If 'Disabled' is selected, pages may not be opened in Incognito mode. If 'Forced' is selected, pages may be opened ONLY in Incognito mode. 
0 = Incognito mode available. 
1 = Incognito mode disabled. 
2 = Incognito mode forced. 

If this is a work system, then the creation and maintenance of this key (and in turn the availability of the option) may be under the control of your network admin.