outlook exp. adding attachm,cant delete

running win XP and using outlook exp. for emauling
outlook exp. doesnt let me delete any mail (inbox, sent items, deleted items etc.) pressing on del doesnt do any any thing.
also senting emails adding an attachment - empty
attachment to the mail.
norton didnt help. installed the HD onto other pc and ru the AVAST AV dint help too.
appreciate your help. thank in advance