Activating Office Web Apps Services on SharePoint
1 Click on the Start button, and then on All Programs
2. Open the Microsoft SharePoint 2010 Products folder under All Programs and click on SharePoint 2010 Central Administration.
3. When the SharePoint Central Administration page opens, go to the System Settings and click on Manage Services.
4. Look for the following services and start them: Word Viewing Service; Excel Calculating Service; and PowerPoint Server. Please note that though OneNote is included in Web Apps, there is no separate service for it so you need not activate it.
You now need to activate the Office Web Apps on the SharePoint server. Before that, you may want to add proxies to the Services so that no one misuses them.
Setup Proxies for Office Web Apps on SharePoint (Optional Step)
1 Open the SharePoint 2010 Central Administration as explained in above section.
2 Go to Application Management and click on Manage Service Applications.
3 The Service Applications window opens. Click New and then click on Word Viewing Service.
4 A new dialog opens. Under Name, type Word Viewing Service Application. Under Application Pool, select Use Existing. In the list that appears, scroll down and select SharePoint Web Services Default. Check Add This Service Application's Proxy to Farm's Default under Add to Default Proxy List. Click OK to close the dialog.
5 Repeat steps 4-5 again for Excel and PowerPoint services. Replace the Name: PowerPoint Service Application for PowerPoint Service Application and Excel Services Application for Excel Services Application.