Configuring Sandboxed Solutions - Cannot start service SPUserCodeV4 on computer

When you built and deploy SharePoint 2010 solution using Farm it will deploy successfully.

But when you create a SharePoint 2010 solution using Sandboxed it may throw an Error

Error occurred in deployment step 'Activate Features': Cannot start service SPUserCodeV4 on computer 

The error can be easily resolved by starting the Microsoft SharePoint Foundation Sandboxed Code Service which can be accessed through the Central Administration site in SharePoint.   Open the Central Administration site and go to System Settings and click on Manage Service on server:

Check to see if Microsoft SharePoint Foundation Sandboxed Code Service  is running

If it is Stopped, then Start the Service and Deploy the Sandboxed Solutions.