Safe mode will boot up your computer with only the bare minimum loaded. So if the files cannot be deleted because they are in use in normal mode then safe mode might allow you to delete them since they might not be in use in safe mode.
the above replys will only work if the files are in use and therefor canot be deleted if the files are marked read only then that can also cause you not beeing able to delete it in what case you need to co to the files in the command prompt and use the attrib command to make it read only again. in the command prompt if they where in the c drive for instance your command will look like this c:/attrib -r -a -s -h c:/"filename"
to make it easier to work with rename the file first to something easy before you use attrib
let us know
if you are not sure about attrib use attrib /?