I don't usually like messing with the System Volume Information folder, and certainly not when System Restore is turned on.
This is a hidden folder and you need to unhide it in Windows Explorer > Tools > Folder options, then the "View" tab. Remove the tick for "Hide protected operating system files, (Recommended)". Whilst you are there, make sure that "Show hidden files and folders" is selected.
Be sure to re-hide the protected OS files when you are done, but the other can remain unhidden.
You don't say what that file name is so we can't check, but I would be wary attempting to delete just any file.
I had noticed a drastic reduction of the free space on my HD (Vista Home Premium) and ran a utility called Free Disk Analyzer. It turned out I have unrecognized files in the System Volume Information folder, but when I go to it in Explorer they are not there! So obviously I have no idea how to delete them.
And yes, of course I have already deleted all restore points etc., and even disabled system restore for a sec to see it this would do the trick, but it didn't. I also resized the maximum shadow storage, to no avail.
I think the unrecognized files could have been left over by Nero Automatic Back It Up, which should now be disabled, but the files are still there and I cannot get rid of them.
Any advice please? I really want to get rid of those files.