Hi Sasi,
Fyi,
Some discussions:
Change the frontpage of Bi Launchpad
BI Customization-Can we change the font color in BI launchpad
Customize BI lunch pad login screen | SCN
Follow guides/ documents mentioned in respective posts.
Like:
How to Add FONTS to BI 4x Platform & WebI Rich-client
Tutorial: Branding and Theming of BI launch pad
Hope this helps.
Regards,
Onkar