Open your registry and find the key below.
Create a new string value, or modify the existing value, named 'IconVerticalSpacing' and set the value to equal the number of pixel to appears vertically between icons, for example '62'.
You may need to restart Windows for the change to take effect.
Key:[HKEY_CURRENT_USER\Control Panel\Desktop]
Value Name: IconVerticalSpacing
Data Type: REG_SZ
More info: http://support.microsoft.com/support/kb/articles/Q102/5/36.asp
