(1) You can't delete them because they have special attributes that won't let you delete them. Do this:
Start-Run-cmd
Type:
cd\
At the c:\ prompt cd to the dir that the files are in, type the following:
attrib -r -a -s -h *.*
then try deleting all the files in that dir by typing
del /f *.*
The /f switch will force delete files with read-only attribute (just in case) The files should delete. You should do the same thing if there are any subdirectories.