Parse Html Document Get All input fields with ID and Value

I have several thousand (ASP.net - messy html) html generated invoices that I'm trying to parse and save into a database.

Basically like:

 foreach(var htmlDoc in HtmlFolder)
 {
   foreach(var inputBox in htmlDoc)
   { 
      //Make Collection of ID and Values Insert to DB
   }
 }  

From all the other questions I've read the best tool for this type of problem is the HtmlAgilityPack, however for the life of me I can't get the documentation .chm file to work. Any ideas on how I could accomplish this with or without the Agility Pack ?

Thanks in advance