hi,
https://officeapi.codeplex.com/[
^]perfectly meet your requirements.As far as I know, it has newly add PPT processing feature into its Office suite case so you can mannage both .ppt and .doc file.And you are allowed to build any type of a 32-bit or 64-bit .NET application including C#, VB.NET, ASP.NET, Web Services and WinForms for .NET Framework version from 2.0 to 4.5 without Office Automation.
hope it helps.