Help Concatenate All Cells In A Column To A Single Cell In Another Column

I have three columns. Column A has a list of file names. Column B has each cell filled with the word OR. Column C Concatenates Columns A and B together to give me something like this:

Document01 OR
Document02 OR
Document03 OR
Document04 OR

What I'd like to do with this is concatenate all of the cells in Column C into the first cell of Column D, to give me something like this:

Document01 OR Document 02 OR Document03 OR Document04

I can then copy and paste that cell into a search box in windows (or another file finding program) to find all of the files I originally pasted in Column A.

I have everything working except that I have to edit the formula in the first cell of Column D by hand, adding every cell I'd like to concatenate to it like this:

=CONCATENATE(C2,C3,C4,C5,C6,C7,C8,C9,C10,C11,C12,C13,C14,C15,C16,C17,C18,C19,C20,C21,C22,C23,C24,C25,C26,C27,C258,C29,C30,C31,C32,C33,C34,C35,C36,C37,C38,C39,C40,C41,C42,C43,C44,C45,C46,C47,C48,C49,C50,C51,C52,C53,C54,C55,C56,C57,C58,C59,C60,C61,C62,C63,C64,C65,C66,C67,C68,C69,C70,C71,C72,C73,C74,C75,C76,C77,C78,C79,C80,C81,C82,C83,C84,C85,C86,C87,C88,C89,C90,C91,C92,C93,C94,C95,C96,C97,C98,C99,C100)

Is there an easier way to do this? Note that I won't always know exactly how many cells I'll have filled in Column A. If I could make it concatenate infinately that would be great. Or at least up to 2000 if that's possible. Sorry if this is a stupid question, I'm new to excel and formulas.

I've attached a copy of what I have so far.

Thanks!