Toni
That would depend upon how they became "lost".
Did you save over them and now want to undo the damage? Not likely possible.
Did you send them to the recycle bin then emptied it? They are gone!
To recover deleted files there are commercial products out there that, for a
fee, will recover files.
MAIN THING........quit using your computer(turn it off) because the space
taken up by the "lost" files could get over-written.
More detail would be in order. Post back from someone else's computer.
Gord Dibben Excel MVP