1. On the SharePoint Server go to the Themes folder e.g. C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\THEMES 2. Copy any one of the theme folders from there and paste it in the same directory and give the folder a unique name, say "MyCustomTheme". 3. Find the .inf file in the copied folder, and rename it with the name given to the folder i.e. in this example rename that .inf file with MyCustomTheme.INF. 4. Open the .inf file and assign the same name i.e. MyCustomTheme to the title in the [info] section of the file, and in the [titles] section replace the previous names with your new name. 5. There is one theme.css file in that MyCustomTheme folder, open that, delete all the classes from that file and place your own css classes in that file. 6. Open “C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\LAYOUTS\1033\SPTHEMES.XML” file with notepad 7. Add the following...