There is a lot of information on the web from the major antivirus companies about the BLACKMAL Virus. Put "BLACKMAL Virus" into google and you will find a lot of informaiton.
It seems that this virus has a destructive payload and deletes files. I have not found any information about it leaving 1kb files, but this may be the case.
Before you attempt recovery, I would suggest that you download and use a Blackmal virus removal tool (there is one at symantec). Also update your virus scanner and try and make sure that you system is clean.
To get your files back, download and run Recover My Files from
www.recovermyfiles.com. I suggest you run a "Complete File Search" for specific file types. In the results screen, click on the files found to preview their content to make sure you are getting back your missing files. When you save the files, make sure you scan them again to ensure that they are virus free.
Please let me know how this goes. The virus may have done some other tricky things with the file size which may require a different type of search technique.