Hi andy
There are many file recovery utilities available on the 'net. Just try a Google search on "file recovery NT". Unfortunately not many of them are free and most are quite expensive to buy
The main thing is not to use the PC until you have some suitable file recovery software.
You will need to remove the drive from your PC and install it as a slave drive in another PC running NT, 2000 or XP.
File recovery software should never be installed on the drive where the lost file(s) are kept, as installing software on it could reuse the space used by the delete file.
I hope this help. Please post back if you need more information