System.Diagnostics.Process.Start(@"C:\WebApplication1\DSE desk_worksurface_work env_routine 2010.ppsx");
use this and this wil play the pps or ppsx file directly when you load your page or by any click button or in iframe, but use also the below class and refrences.
using Microsoft.Office.Core;
using Microsoft.Office.Interop.PowerPoint;
using ppt = Microsoft.Office.Interop.PowerPoint;
using System.Runtime.InteropServices;