programs missing please help!

Hello,
I am running XP Home. Recently I noticed that I am missing
(at present) the "Paint" program plus a file
labelled "Windows NT" which for some reason includes a
pinball game that came with XP. And,I am also
missing "Sound Recorder." The icons are still on my screen
but when I click on them a message appears that tells me
that the programs in question have been moved or are
missing. Can you tell me where they may be if they are
possibly still on the computer. Thanks for you help in
advance! Stephen