Couple of things, what software is it that you are using, if it is burn for free, then use something else as its not very good.
ANY file burnt to a CD/DVD should be visable within a PC CD/DVD player, the fact that it is only visable in a standalone DVD player would indicate that the software has changed the format to one IT uses itself.
Use Nero for every burning requirement, some people prefer Roxio, but I prefer Nero, It supports ISO, Data, VOB and many others and is good for beginners and advanced users.