On *another* computer with a CD burner, download testdisc/photo rec from
TestDisk Download - CGSecurity. Burn the CD image to a CD. It's important to stop using the problem PC to prevent your missing files from being overwritten.
Boot the problem machine with the Testdisc/Photorec bootable CD. It can be used to scan the hard drive for the raw data that composes your files without writing to that drive. Because it's looking for file type bits it can circumvent operating system issues. If the file's bits can be read the file can be recovered. You'll need an alternative storage for found files to be copied to and recovered files won't have their original filename - but at least you get your files back.