I went through the Word to PDF pain when someone dumped me with 10000 word files to convert to PDF. Now I did it in C# and used Word interop but it was slow and crashed if I tried to use PC at all.. very frustrating.
This lead me to discovering I could dump interops and their slowness..... for Excel I use (EPPLUS) and then I discovered that you can get a free tool called Spire that allows converting to PDF... with limitations!
http://www.e-iceblue.com/Introduce/free-doc-component.html#.VtAg4PmLRhE
