Prevent specifying the hover color
Supported on: At least Internet Explorer 7.0
Registry
HKCU
Software\Policies\Microsoft\Internet Explorer\Settings Options
Anchor Color Hover text Description
This policy setting prevents the user from specifying the color to which hyperlinks change when the mouse pointer pauses on them. If you enable this policy setting, the user cannot specify the hover color. You must specify the hover color (for example: 192,192,192). If you disable or do not configure this policy setting, the user can specify the hover color.