Welcome Paigeypar to the windows 7 forums.
There is the possibility that the .psd files that you created are not compatible with the intel version of photoshop.
or, your zip program is only zipping up the fork files and not the data files. Not being a mac person, I do remember from my mac days that the mac uses two files to make a pair, one being the resource fork and one being the data fork. Most pc's ignore the resource fork and only use the data fork.
Hope this helps