One way I've found of getting around this issue (I googled it a while back and found it) is to get ghostscript to embed the fonts in the document. My understanding is that a certain set of fonts are supposed to be a part of every pdf viewer, so these are often not embedded in the document itself. This trick tells ghostscript to change the text into curves etc. and hard code them into your document. The side effect is that you can no longer select text, but at least it looks identical.
One way I've found of getting around this issue (I googled it a while back and found it) is to get ghostscript to embed the fonts in the document. My understanding is that a certain set of fonts are supposed to be a part of every pdf viewer, so these are often not embedded in the document itself. This trick tells ghostscript to change the text into curves etc. and hard code them into your document. The side effect is that you can no longer select text, but at least it looks identical.
gs -sDEVICE=pswrite -dNOCACHE -sOutputFile= nofont- MyDocument. ps -q -dbatch -dNOPAUSE MyDocument.pdf -c quit MyDocument. ps nofont- MyDocument. pdf
ps2pdf nofont-
Where you replace MyDocument.pdf with your pdf or ps document. I've not tried this on windows, but it works on Linux and OSX.