If using Internet Explorer you may be unable to view the contents of the downloaded CHM file. There are two methods for resolving the problem:

Method 1

1. Download the .chm file to a folder
2. Double-click the .chm file.
3. In the Open File-Security Warning dialog box, click to clear the Always ask before opening this file check box.
4. Click Open.

Method 2

1. Download the .chm file to a folder
2. Right-click the CHM file, and then click Properties.
3. Click Unblock.
4. Double-click the .chm file to open the file.

For more information see Microsoft.com - You cannot open HTML Help files from Internet Explorer after you install security update 896358 or Windows Server 2003 Service Pack 1