pdf to word doc converter and/or pdf merger

i have many pdf files i want to convert merge together into one pdf/word document.

i am looking for any free pdf to word converter
or
a pdf COMBINER software that can give me one comprehensive pdf file.

I have tried a couple of options already and they dont seem to work = http://www.pdftoword.com/Default.aspx
and
http://www.hellopdf.com/


Does anyone here know any software or website of either variety that actually works??