The problem may be that these were writen in Office 2007 or Office 2010, there is a compability patch (see fruitbat), but I do not know if if applies to office 2002.
I believe the converted files (2007 to an earlier version) are locked, which is why you are having a problem deleting themand for the same reason they appear as corrupt.-Your office software is not able to read the format correctly.
On your office software, are the extentions 'hidden', if so you will need to show these extentions (look under folders in the top bar)and unhide them. you should then be able to delete or change them.
Your software is well out of date and I suggest you use a program like Openoffice (free) see link for info and downloads for your office software.