I have a wpf file. I cannot open it in a word program. Is there a way to convert the wpf file to doc without me having to install any software? For free?

Do you have anything in the document other than words? If so, than it would help to know which version of Word Perfect it is that you have. Also, if you know how to do so, perhaps just copying and pasting into another document format might do the trick.

What other word processing programs do you have on your computer, please?

Some links found on the following search might also be helpful to you. I hope that they are. Free Conversion of Word Perfect Documents - Google Search

Just some thoughts for you...

Where did you get this file? Do you know what program was used to create it?