How to show more than 3 dashboard components in Salesforce?

Hi Pranav,

Goto YourName-->setup-->Customize-->home-->Home page components
Click New to create a custom components,
Give the Name to the components and then select HTML area
After that Select show HTML check box as shown in the screenshot
Then paste the following code,
<iframe src="/00000000000?isdtp=lt" frameborder="0" height="900" width="1280"></iframe>

Note:-/000000000 is the Id of the dashboard,change that into your dashboard Id which you want to display in the Home page.

Thanks